So I've played through BGEE and BG2EE a few times now and I've tried all the new NPCs. (I also tried out most of the new ones in SOD but only once). They all have merit and I can tell a lot of work went into each one. I don't want anyone to think I'm "anti" any of the NPCs here.
But gosh, I just LOVE Hexxat.
If you haven't read the title, there are major spoilers after this, so please stop and don't ruin it for yourself if you haven't gotten her. Half the fun of Hexxat is the mystery surrounding her!
1. Recruiting Hexxat
Hexxat has by far the most unique recruitment of all the NPCs. You start out meeting Clara who says she is Hexxat and appears to be touched in the head. Regardless she claims to know a nearby tomb full of riches and magic items, and what adventurer can resist that? (It both amuses and annoys me to NO end that so many people thought Clara really was to be the real NPC you get and complained up and down the forums about it. Even I realized that there was more than meets the eye to her and that it would be interesting and worth it to follow the girl and see where it led.) Of course you learn the tomb is a trap and that a vampire guards it. You find Hexxat is really another person (who has a great portrait and voice acting) who is also a vampire and who, without hesitation, drains poor Clara to death to effect her freedom. That is awesome writing.
2. Hexxat's Questline
I enjoyed both Neera and Rasaad's quests but man nothing tops the Indiana Jones quests of Hexxat. She is like the evil Dr. Jones who is stealing artifacts not for a museum but for a mysterious private collector with likely nefarious purposes - and she just doesn't care either. The exotic destinations you are whisked away to on her missions are unlike any other. Heck in your first two you go to Kara-Tur AND Al-Quadim. That is amazing stuff. Each had just the right amount of traps, puzzles and monsters.
3. Hexxat is a Vampire!
And not one of these new fangled sparkly vampires who aren't really evil vampires. She's a real vampire. She drinks blood, she kills people, she has (almost) no remorse. She has cool abilities. She is immune to a ton of things that easily dispatch others, like energy drain.
4. The Cloak
At first I thought the Cloak of Dragonmir would be really annoying, but it isn't. It adds a measure of balance to an otherwise OP character and a great RP dimension to her. She's a bad A vampire but she depends
on the PC to a certain extent. Plus, free bag of holding!
So your PC is a god-child and part of an epic prophecy surrounding the Lord of Murder and his imminent return. *Yawn* Hexxat could care less. She's so blase about your quest and your needs, all she cares about is her missions and what she can get out of adventuring by your side. The fact that the lives of millions rest on your shoulder is almost *amusing* to her. But there's more to her than meets the eye: she has some kind of standard. She makes remarks every now and then alluding that she wishes there were a way out, and she refuses to turn Dorn when he asks because she does not want to spread her curse to others. She's evil, but it's an evil you just can't hate.
6. The Mysterious L
This one's such a big spoiler I won't even disclose it here. As a big Realms fan, I suspected who it was as soon as I knew his name was L. There's only one powerful evil dude in the Realms who regularly employs and half-enslaves other powerful undead to be his gophers whose name starts with L. Great touch to a great storyline.
Anyways, to Beamdog, whoever on your team came up with Hexxat, they did a FANTASTIC job. Hexxat is as cool, unique, and interesting as the NPCs from PLANESCAPE: TORMENT, and you know that's saying something!