Yeah, don't think it can get any better than Larloch. He survived the fall of Netheril, back when mages truly were almost gods, and is a ~2000 year old Lich by the time Charname begins his journey. And as far a liches go, he seems a pretty nice albeit insane guy, considering he just wants to be left alone researching magic instead of dominating the world or doing some other chaotic stupid activity. Hell, he was already a lich like 800 years before Elminster was even a baby.
In the FR, the most powerful being that is not a god, that is still "alive" or existing on Toril would be the Oracle of Ellyn’taal, also known as Ioulaum. He was the greatest of Netheril's archmages, was 41st level at the time of the fall of Netheril, then became a lich, and still later enslaved illithid liches to create a giant undead Elder Brain, which he then fused with. By 3.5 rules he is CR 68, and one of the oldest beings on Toril, something like 5500 years old. Can't think of any being ever listed higher.
In the FR, the most powerful being that is not a god, that is still "alive" or existing on Toril would be the Oracle of Ellyn’taal, also known as Ioulaum. He was the greatest of Netheril's archmages, was 41st level at the time of the fall of Netheril, then became a lich, and still later enslaved illithid liches to create a giant undead Elder Brain, which he then fused with. By 3.5 rules he is CR 68, and one of the oldest beings on Toril, something like 5500 years old. Can't think of any being ever listed higher.
I was going to say that Azmodeus is one of the strongest but then I checked and he was a greater deity, so he is out of the list, I guess.
I found this in wikipedia. It is interesting:
Belcheresk was a potent Balor and the Demogorgon's right hand. Major Enderan a demon in command of a company of stone giant juju zombies. War Secretary-General Gromsfed the Drowned was a huge klurichir 4th warchief who was the chief tactician of Demogorgon. Saint Kargoth the Betrayer the first death knight and one of the Demogorgon's top generals. Kazuul the exarch of Demogorgon. Archpriest Nulonga was an ancient worshiper of Demogorgon. Rozvankee was a female Lich pirate and one of the best monster creator in service of Demogorgon. Severik was a potent Balor that command the elite marilith Demogorgon's bodyguard squad. Tharak was an ettin clone of Demogorgon and one of his best monster creations.
From Baldur's Gate(Sahuagin City, Riddle of the Imps) I know Alustriel, Piergeiron, Khelben, Elminster and Drizzt which are portrayed as powerful heroes of Forgotten Realms. Well, Drizzt, Khelben and Elminster are widely known of course.
@Heindrich Probably Szass Tam. He comes near to becoming a God at one point (albeit in a novel). Most powerful character? If you want to say "Powerful", you'll have to define in what way powerful? Ability to cast spells? HP? Liches are pretty powerful (Szass Tam is a lich), but they cannot gain levels once they move over into being undead (By 2e rules, anyway. I heard this may have changed in later editions.) Elminster is also pretty powerful as a spell caster, and he's also a Chosen of Mystra, charged with carrying some of her "Silver Fire", which may be part of her Godhood. It's also how they are going to bring her back for D&D Next- with the survival of Elminster and at least some of the chosen, Mystra can/will reconstitute herself from the parts of her godly powers they carry.
Now, since they were also part God but human, I'd have to say Cyric and Midnight near the end of the Time of Troubles were pretty damn powerful- each was carrying the power of one (Midnight/Mystra) or several (Cyric/Bane, Bhaal and Myrkul as well as the sword form of the God of Thieves, Mask). But they were still human until the end and ascended to being Gods, just as CHARNAME does (possibly) at the end of BG2. Even a Level 46 Mage Lich is not going to be able to stand against a God. So, if backed into a corner, I'd say Cyric at the end of the Time of Troubles, before he ascended to being a God. He was hampered by insanity later, but he was personally pretty damn powerful at the time. Second was probably Midnight/Mystra, since Mystra is the Goddess that powers ALL magic EVERYWHERE in the Realms. When she "died", that's when you get stuff like the Spellplague, where magic works completely wonky and inconsistently.
As for the poster who mentioned Karsus "Killing" Mystra, he didn't actually do that. What he did was try to usurp the power of the Goddess (Known at the time as Mystryl). She didn't get killed, she sacrificed her divine essence to save the weave from Karsus, who was unable to control it, not having the experience with doing so that Mystryl had. His "ascension" was also what set off the fall of Netheril. Ironically so, since by using his spell, he was trying to save Netheril from the Phaerimm.
Most powerful character in FR settings? You can say King Oreme also knowed as Arthindol The Terraser A Sarruk lich wizard 25 archmage 5 +14 racial HD. He was the master of the first nether wizards, master of Karsus, he wrote the famous nether scroll. A total CR of 53 he has at least 10.000 years old. Szass Tam, Larloch ? only children
The most powerful non-divine being that still exists on the Prime Material Plane, in Abeir-Toril is likely Larloch, the king of Warlock's Crypt. He has undoubtedly surpassed Loulam at this point, since Loulam hasn't been doing anything other than role-playing the Oracle for adventurers whilst Larloch has been collecting enough magical fire-power to conquer a continent over night. He has a whole network of liches and demi-liches that he controls through mental domination. Even the ruler of Thay, Szass Tam answers to Larloch.
There are other beings, but I've forgotten what they're called. Something along the lines of "Elder Evils" ...or something. They are mostly monsters with origins in the far-realm, such as planet-sized aboleths floating through space and devouring everything they come across. I'm sure at least one of those is at least as powerful as a greater deity, without being divine beings themselves.
I don't think Szass Tam answers before Larloch. In fact Tam is one of a really few individuals who isn't Larloch's servant who came out from Warlock's Crypt alive. With quite powerful artifacts on top of that. Frankly, Larloch was nerfed in 3rd edition and I think Daurgothoth "The Creeping Doom" is in fact more powerful than Nethersee lich.
Ancient Elder Brain Lich 41 level Wizard/Archmage/Netherese Arcanist.
Not only he has the standard lich's properties, he's the big boss of Mind Flayers (Elder Brain), plus an epic arcanist with knowledge from the ancient Netheril. Plus he's a lich.
Not sure which one is strongest, Larloch or Ioulaum. According to Greenwood, he's much more powerful than his stats and around 40+ level.
Daurgothoth is pretty powerful as well. Combining three of the most possible beings. A lich, a dragon and an epic Wizard.
Szass Tam is pretty behind the curve compared to Ioulaum and Larloch.
I would say that roughly the ranking goes like that: Ioulaum > Larloch > Szass Tam > Daurgothoth.
Ioulaum is officially the most powerful by levels and abilities, though Larloch commands an army of demiliches/liches/vampires and has pages of the Nether Scrolls.
While Szass Tam commands humans and respects Larloch. And probably knew than in a straight fight, he would annihilated by Larloch.
Daurgothoth might not be the most powerful arcanist but he has his own group of undead dragons and he himself is an epic Black Dragon with huge physical stats as well as magical knowledge.
Elminster comes close as well, though his only advantage is his Silver Fire.
After some research, I also found this. Quoted text from Ed Greenwood himself take from the Candlekeep forum:
"Larloch is a onetime Netherese sorcerer (still possessed of a lot of Netherese scepters, which he knows how to make) who is now a quite insane "ultra-lich" (in this case, the term means he has many unknown powers which are up to you the DM, among them the fact that he can still learn and develop new spells, increase in levels, etc.). He's probably a 46th level evil-aligned wizard right now, and he crafted many of his own undead abilities prior to undeath, which argues that he found his own 'process' for achieving lichdom. Larloch is served by many (60+ ?) liches, formerly archwizards, whom he guides in concert, as the leader of a telepathic-web 'Overmind.' Thus far, neither psionics nor mind-influencing magics have ever been effective against him or any of his serviotr mages, because the others in the link can withstand and overcome such influences, causing them to fail. In theory, an attack could reach all of them through the link, but some quite powerful Red Wizards have tried and failed (Szass Tam didn't try such an attack, which may be why he survived...he remains fearful of approaching Larloch and his mages, but fascinated by the details of their lichdom, hoping it might yield him some powers.) One of Larloch's given-to-himself powers (which - in a long, involved, and secret, personally-developed process - cost him 10 years of life and some vitality, irrelevant of course given his goal of lichdom) is automatic spell reflection (of all magic cast upon him). He can by act of will override this ability, for example when he wants to work a spell on himself; otherwise, it always operates. Mystra (Midnight's predecessor as the goddess) is said to have allowed Larloch to acquire powers approaching those of "old Netheril" in return for 'leaking' spells to persistent adventurers he or his minions might come into contact with, but this may be no more than rumour spread by the Zhents or Red Wizards or Dragon Cultists, designed to lure adventurers into Larloch-weakening forays... As for Larloch knowing the identities and locations of other liches/Netherese survivors...no, only the one's he's destroyed. Larloch is too self-centered to hunt down folks who don't come within his easy reach. He controls plenty of archwizards/liches already, but may decide to try to either control or destroy a new one when they come into contact. He seems to be pursuing other goals, however. Which ones? That's up to each DM....." Larloch and his lich minions have no interest in attracting attention that would waste their time and magical resources (and perhaps, if word got around how dangerous they were, even threaten their existence in the face of a concerted attack from various magical power groups working together). Larloch is not interested in ruling Faerun...but he IS interested in creating and controlling a series of magical gates linking many worlds (parallel Prime Material Planes) and Outer Planes...and so rigging their enchantments that anyone using them comes under his control/faces his forceful removal of their magic items, information from their mind, and so forth. The gates are easy for him to create (he licked all of those problems long ago). The control enchantments have been giving him troubles for thousands of years now, and as an obsessive perfectionist, he isn't going to let this rest until he gets everything just so...nor is he going to create the gates until he's ready to put the controls on them. In short, he's a munchkin only if played that way. All Player Characters have to learn sometime that there are folks in the Realms just too powerful to tangle with. I'm reminded of the original Realms campaign, and the Company of Crazed Venturers attacking Shaan the Serpent-Queen (who briefly appeared in a Wizards Three DRAGON article). She was busy working magic on a small island off Mintarn. They attacked, broke her concentration, and she looked up with an irritated frown. They bid her stop, or they'd destroy what she was working on; to demonstrate, one of the Company mages touched (and disintegrated) a stone he was standing beside. She shook her head in derision, and touched the island beneath them, disintegrating IT, and dumping the Company into the chilly sea waves for a long swim...whilst she turned back to her spellcasting, floating on nothing and ignoring them once more. A heavy-handed lesson, but...well, Larloch's in the same league, and more. Just consider him a power of the Realms and Don't Go There. Ed"
Well, there is one more badass we forgot about - Qysar Shoon VII. While he was being imprisoned within artifact known as the Tome of the Unicorn he was able to free himself during the Time of Trouble chaos, by swapping bodies with female moon elf mageling. And he is in fact a demilich necromancer 31/archmage 5 by 3.5ed standards. He transformed himself into demilich after several centuries of lichdom and is now plotting to put Shoon Imperium back on its track.
It's very difficult to estimate which one of the list possess more personal power to be honest. I think at the time of Netheril both Ioulaum and Karsus were probably the most powerful arcane users of their times. Karsus ended badly because of his craving for power. Ioulaum has managed to avoid repercussions of the falling of Mystra and went on the route of becoming Elder Brain. Larloch carved his own mini-kingdom with hundred of thralls, amasing the magical power and lore to the extend of which he is probably more powerful than Ioulaum (they've hurt him awfully in 3.5ed if you ask me). Daurgothoth is in fact very capable arcanist who is experimenting with different breath types and can in fact use several breath attacks not available to normal black dragons. And he is one of the leaders of the Cult of Dragon - he has every resources to be a badass. I would put him above Szass Tam when comes to magical powers, but below Larloch and Ioulaum.
Szass Tam - while he is very powerful he lives not nearly as long as Ioulaum, Karsus or Daurgothoth or even Elminster. While he is definitely most powerful individual in Thay, he is definitely not powerful lich in the Realms. But I like this guy so much:)
And there is a whole bunch of Twisted Rune lich leaders, all of which could easily match Szass Tam's power to be honest. Although they are not so powerful as Larloch they are the force to be reckon with, to be sure.
The skulls in skull port. Lady Alustriel , Symbol, and pretty much the other daughters of Mystra. And that shadow lord that has power over the shadow enclave.
Is Gromph really powerful enough to be discussed in the same sentence as Elminster? I mean, he's a badass archmage, but he's still only mortal. Unless I'm missing something that's happened recently that changed the game with the guy.
Hell, last I knew, he was archmage of only his specific city (Menzoberanzan? I have no idea how it was spelled), meaning that for all we know the next city over has a mage that could kick Gromph's ass.
I consider him to be a huge impact to the underdark. In my assumption I would consider Gromph to be a lvl 24 archmage. Even great Jarlaxle is scared of his older brother.
Why has nobody mentioned The Srinshee? The Grand Mage of the Grand Mages of Cormathor? Guardian of the Wault of Ages and simple put be Ed Greenwood to be the most powerful caster in FR. Not to mentione she one-shotted Larloch while he was majorly buffed by the Mythal of Candlekeep!!!!
I wanna throw some extraplanar beings into the running: from the Abyss there's Graz'zt and Orcus (along with Demogorgon). The Nine Hells has Mephistopheles and Baalzebub. The celestial paragons include Zaphkiel and Talsid. None of these except Zaphkiel are beings that I believe could defeat Ioulaum or Larloch. Zaphkiel could probably give them a run for their money though.
Possibly the greatest non-deities are the elder evils (although some of them like Dendar have pretty paltry 3.5 stats). One that doesn't have stats and is probably the most objectively powerful being (when it's mind and body are united anyways) is Pandorym. An elder evil from outside the universe which the Imaskari bring as a deterent to an entire pantheon of Gods. In terms of power, one gets the impression that it easily rivals a greater deity. There are many other elder evils as well (the ones from Champions of Ruin and Pandorym are the ones I'm most familiar with). In any case I think that Pandorym especially could probably squash either Larloch or Ioulaum when its mind and body are united.
Finally, if the epic level handbook is canon from 3e you open a huge can of worms including the abominations (hecatoncheries, xixicels, phaethons, dream larva and atropals could all contend here) and even more significantly the prismatic and force dragons. A great wyrm force or prismatic dragon would easily beat ioulaum and most deities and that's not even popping open the question of "Advanced" dragons where they move beyond great wyrm level. The great wyrm prismatic dragon has a challenge rating of 66 and I frankly think that's potentially an underestimation of what it can do. Other honorable mentions in those books would include Elder Titans and Leshay. We know that Force and Prismatic Dragons were canon as of third edition from the Dragons of Faerun supplement and that atropals are canon in 5th edition canon via Tomb of Annihilation (although they're much weaker in 5th edition).
Oh, and two more named characters: High Prince Telamont Tanthul of the Shadovar and Rhangaun of the Twisted Rune (although the Twisted Rune were already mentioned before). Both are wizards with caster levels in the mid 30s. I think Telamont is particularly impressive as an immortal shade with undisputed rule of an entire floating city of shade arcanists.
Comments
Hell, he was already a lich like 800 years before Elminster was even a baby.
I found this in wikipedia. It is interesting:
Belcheresk was a potent Balor and the Demogorgon's right hand.
Major Enderan a demon in command of a company of stone giant juju zombies.
War Secretary-General Gromsfed the Drowned was a huge klurichir 4th warchief who was the chief tactician of Demogorgon.
Saint Kargoth the Betrayer the first death knight and one of the Demogorgon's top generals.
Kazuul the exarch of Demogorgon.
Archpriest Nulonga was an ancient worshiper of Demogorgon.
Rozvankee was a female Lich pirate and one of the best monster creator in service of Demogorgon.
Severik was a potent Balor that command the elite marilith Demogorgon's bodyguard squad.
Tharak was an ettin clone of Demogorgon and one of his best monster creations.
From Baldur's Gate(Sahuagin City, Riddle of the Imps) I know Alustriel, Piergeiron, Khelben, Elminster and Drizzt which are portrayed as powerful heroes of Forgotten Realms. Well, Drizzt, Khelben and Elminster are widely known of course.
So... erm, who's the most powerful necromancer in the Forgotten Realms?
Now, since they were also part God but human, I'd have to say Cyric and Midnight near the end of the Time of Troubles were pretty damn powerful- each was carrying the power of one (Midnight/Mystra) or several (Cyric/Bane, Bhaal and Myrkul as well as the sword form of the God of Thieves, Mask). But they were still human until the end and ascended to being Gods, just as CHARNAME does (possibly) at the end of BG2. Even a Level 46 Mage Lich is not going to be able to stand against a God. So, if backed into a corner, I'd say Cyric at the end of the Time of Troubles, before he ascended to being a God. He was hampered by insanity later, but he was personally pretty damn powerful at the time. Second was probably Midnight/Mystra, since Mystra is the Goddess that powers ALL magic EVERYWHERE in the Realms. When she "died", that's when you get stuff like the Spellplague, where magic works completely wonky and inconsistently.
As for the poster who mentioned Karsus "Killing" Mystra, he didn't actually do that. What he did was try to usurp the power of the Goddess (Known at the time as Mystryl). She didn't get killed, she sacrificed her divine essence to save the weave from Karsus, who was unable to control it, not having the experience with doing so that Mystryl had. His "ascension" was also what set off the fall of Netheril. Ironically so, since by using his spell, he was trying to save Netheril from the Phaerimm.
http://forgottenrealms.wikia.com/wiki/Karsus
You can say King Oreme also knowed as Arthindol The Terraser
A Sarruk lich wizard 25 archmage 5 +14 racial HD.
He was the master of the first nether wizards, master of Karsus, he wrote the famous nether scroll.
A total CR of 53
he has at least 10.000 years old.
Szass Tam, Larloch ? only children
There are other beings, but I've forgotten what they're called. Something along the lines of "Elder Evils" ...or something. They are mostly monsters with origins in the far-realm, such as planet-sized aboleths floating through space and devouring everything they come across. I'm sure at least one of those is at least as powerful as a greater deity, without being divine beings themselves.
Frankly, Larloch was nerfed in 3rd edition and I think Daurgothoth "The Creeping Doom" is in fact more powerful than Nethersee lich.
Ancient Elder Brain Lich 41 level Wizard/Archmage/Netherese Arcanist.
Not only he has the standard lich's properties, he's the big boss of Mind Flayers (Elder Brain), plus an epic arcanist with knowledge from the ancient Netheril. Plus he's a lich.
Not sure which one is strongest, Larloch or Ioulaum. According to Greenwood, he's much more powerful than his stats and around 40+ level.
Daurgothoth is pretty powerful as well. Combining three of the most possible beings. A lich, a dragon and an epic Wizard.
Szass Tam is pretty behind the curve compared to Ioulaum and Larloch.
I would say that roughly the ranking goes like that: Ioulaum > Larloch > Szass Tam > Daurgothoth.
Ioulaum is officially the most powerful by levels and abilities, though Larloch commands an army of demiliches/liches/vampires and has pages of the Nether Scrolls.
While Szass Tam commands humans and respects Larloch. And probably knew than in a straight fight, he would annihilated by Larloch.
Daurgothoth might not be the most powerful arcanist but he has his own group of undead dragons and he himself is an epic Black Dragon with huge physical stats as well as magical knowledge.
Elminster comes close as well, though his only advantage is his Silver Fire.
"Larloch is a onetime Netherese sorcerer (still possessed of a lot of Netherese scepters, which he knows how to make) who is now a quite insane "ultra-lich" (in this case, the term means he has many unknown powers which are up to you the DM, among them the fact that he can still learn and develop new spells, increase in levels, etc.). He's probably a 46th level evil-aligned wizard right now, and he crafted many of his own undead abilities prior to undeath, which argues that he found his own 'process' for achieving lichdom.
Larloch is served by many (60+ ?) liches, formerly archwizards, whom he guides in concert, as the leader of a telepathic-web 'Overmind.' Thus far, neither psionics nor mind-influencing magics have ever been effective against him or any of his serviotr mages, because the others in the link can withstand and overcome such influences, causing them to fail.
In theory, an attack could reach all of them through the link, but some quite powerful Red Wizards have tried and failed (Szass Tam didn't try such an attack, which may be why he survived...he remains fearful of approaching Larloch and his mages, but fascinated by the details of their lichdom, hoping it might yield him some powers.)
One of Larloch's given-to-himself powers (which - in a long, involved, and secret, personally-developed process - cost him 10 years of life and some vitality, irrelevant of course given his goal of lichdom) is automatic spell reflection (of all magic cast upon him). He can by act of will override this ability, for example when he wants to work a spell on himself; otherwise, it always operates.
Mystra (Midnight's predecessor as the goddess) is said to have allowed Larloch to acquire powers approaching those of "old Netheril" in return for 'leaking' spells to persistent adventurers he or his minions might come into contact with, but this may be no more than rumour spread by the Zhents or Red Wizards or Dragon Cultists, designed to lure adventurers into Larloch-weakening forays...
As for Larloch knowing the identities and locations of other liches/Netherese survivors...no, only the one's he's destroyed. Larloch is too self-centered to hunt down folks who don't come within his easy reach. He controls plenty of archwizards/liches already, but may decide to try to either control or destroy a new one when they come into contact. He seems to be pursuing other goals, however. Which ones? That's up to each DM....."
Larloch and his lich minions have no interest in attracting attention that would waste their time and magical resources (and perhaps, if word got around how dangerous they were, even threaten their existence in the face of a concerted attack from various magical power groups working together). Larloch is not interested in ruling Faerun...but he IS interested in creating and controlling a series of magical gates linking many worlds (parallel Prime Material Planes) and Outer Planes...and so rigging their enchantments that anyone using them comes under his control/faces his forceful removal of their magic items, information from their mind, and so forth. The gates are easy for him to create (he licked all of those problems long ago). The control enchantments have been giving him troubles for thousands of years now, and as an obsessive perfectionist, he isn't going to let this rest until he gets everything just so...nor is he going to create the gates until he's ready to put the controls on them.
In short, he's a munchkin only if played that way. All Player Characters have to learn sometime that there are folks in the Realms just too powerful to tangle with.
I'm reminded of the original Realms campaign, and the Company of Crazed Venturers attacking Shaan the Serpent-Queen (who briefly appeared in a Wizards Three DRAGON article). She was busy working magic on a small island off Mintarn. They attacked, broke her concentration, and she looked up with an irritated frown. They bid her stop, or they'd destroy what she was working on; to demonstrate, one of the Company mages touched (and disintegrated) a stone he was standing beside.
She shook her head in derision, and touched the island beneath them, disintegrating IT, and dumping the Company into the chilly sea waves for a long swim...whilst she turned back to her spellcasting, floating on nothing and ignoring them once more.
A heavy-handed lesson, but...well, Larloch's in the same league, and more. Just consider him a power of the Realms and Don't Go There.
Ed"
It's very difficult to estimate which one of the list possess more personal power to be honest.
I think at the time of Netheril both Ioulaum and Karsus were probably the most powerful arcane users of their times. Karsus ended badly because of his craving for power. Ioulaum has managed to avoid repercussions of the falling of Mystra and went on the route of becoming Elder Brain. Larloch carved his own mini-kingdom with hundred of thralls, amasing the magical power and lore to the extend of which he is probably more powerful than Ioulaum (they've hurt him awfully in 3.5ed if you ask me).
Daurgothoth is in fact very capable arcanist who is experimenting with different breath types and can in fact use several breath attacks not available to normal black dragons. And he is one of the leaders of the Cult of Dragon - he has every resources to be a badass. I would put him above Szass Tam when comes to magical powers, but below Larloch and Ioulaum.
Szass Tam - while he is very powerful he lives not nearly as long as Ioulaum, Karsus or Daurgothoth or even Elminster. While he is definitely most powerful individual in Thay, he is definitely not powerful lich in the Realms. But I like this guy so much:)
And there is a whole bunch of Twisted Rune lich leaders, all of which could easily match Szass Tam's power to be honest. Although they are not so powerful as Larloch they are the force to be reckon with, to be sure.
Father of Draconis (ToB) and that templar single duel lady in SoB, if you are a swashbucker rogue.
Drizzt probably would be, but my alignment would not allow to confrot him.
Possibly the greatest non-deities are the elder evils (although some of them like Dendar have pretty paltry 3.5 stats). One that doesn't have stats and is probably the most objectively powerful being (when it's mind and body are united anyways) is Pandorym. An elder evil from outside the universe which the Imaskari bring as a deterent to an entire pantheon of Gods. In terms of power, one gets the impression that it easily rivals a greater deity. There are many other elder evils as well (the ones from Champions of Ruin and Pandorym are the ones I'm most familiar with). In any case I think that Pandorym especially could probably squash either Larloch or Ioulaum when its mind and body are united.
Finally, if the epic level handbook is canon from 3e you open a huge can of worms including the abominations (hecatoncheries, xixicels, phaethons, dream larva and atropals could all contend here) and even more significantly the prismatic and force dragons. A great wyrm force or prismatic dragon would easily beat ioulaum and most deities and that's not even popping open the question of "Advanced" dragons where they move beyond great wyrm level. The great wyrm prismatic dragon has a challenge rating of 66 and I frankly think that's potentially an underestimation of what it can do. Other honorable mentions in those books would include Elder Titans and Leshay. We know that Force and Prismatic Dragons were canon as of third edition from the Dragons of Faerun supplement and that atropals are canon in 5th edition canon via Tomb of Annihilation (although they're much weaker in 5th edition).
https://forgottenrealms.fandom.com/wiki/Karsus
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