It's Likely impossible - Rage Mage

Otherworldly

The Rage mage, it's a prestige class in 3rd edition. Basically the class was a cross between a barbarian and a mage with the ability to go into a spellrage that increased his spell power in a similar way rage increases melee damage. I really liked this alternative concept in a fighter/mage, and would like to see it included in the game as a kit. I'll admit it's overpower compared to the typical 2e kit structure, but I love the uniqueness.. I would include it as a barbarian kit that essentially make you into a muti-class barbarian/mage including meeting a minimum intelligence score. You would have to earn the experience as a multi-class character as well, and you would likely get diminished spell cast (say 1 less spell per level). I'll list the rage mage abilities.

Rage Mage
Hite Die: d8.
Alignment: Any non-lawful
1st Rage 1/day
2nd overcome spell failure
3rd Spell Rage 1/day
4th -
5th Rage 2/day
6th -
7th spell fury
8th Spell rage 2/day
9th tireless rage
10th warrior cry & Rage 3/day

Spell rage allows you to cast spells while raging on top of that the spell is more difficult to save against the rage mages spells while he's raging.

Overcome spell failure allows you to spell cast in leather armor.

With Spell fury you can cast a spell quicker while in a spell rage.

With Warrior cry once per day you may cast the spell tenser's transformation.

It's a long shot but I always wanted to play this class in a video game format if it's at all possible. My idea was for a tiefling rage mage, but since teiflings aren't implemented I would except human or half-elf.

Grieg

You should change Discussion Title because it is really confusing and/or maybe try a shot in modding section.
I like the idea casting spells only sometimes in the rage:}

Nifft

This might be cool as a Sorcerer or Bard kit.