http://steamcommunity.com/sharedfiles/filedetails/?id=289346138

Issues with installing the mod? Try this (thanks to seraJard@Larian forums):
if you can't find this mod in your mod directory after downloading, you should be able to find it by going here:

*\Steam\userdata\

Then hit CTRL+F and search for: reworked_madora_&_jahan_[number].pak
Move this file to *:\Users\[username]\Documents\Larian Studios\Divinity Original Sin\Mods

Mods most likely do not work together and require a new game to be started. These are unresolvable issues at the moment. So stick to one mod or combine files manually. (That could be a lot of work!)

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Both companions have reworked stats, skills, abilities and talents. Everything is balanced as if they went through character creation, except for some minor stat tweaking to make them stand off on their own.
They start out at level 1, so they level up to the player's level once you let them join.
Matching equipment for these changes.

Changed Madora to a sword-and-shield fighter so she now acts as a tank.

Jahan has Aerothurge, Pyrokinetics and improved Willpower.

He now has better synchronisation with a player-created wizard with spells of the opposite schools; Hydrosophy and Geomancy.
If you do not create a wizard of your own, he just has a different build.

This allows you to chainlink spells within the same turn, for extra damage. As opposed to vanilla Jahan, who had two schools that complimented each other, which would take two turns to chain. By combining two wizards, they can chain in the same turn.
Mind you, this chainlinking will only work if you create a spellcaster with opposite schools.

For instance:
Turn 1: Player casts Midnight Oil -> Jahan casts Firebolt
Turn 2: Player casts Rain -> Jahan casts Blitzbolt
vs.
Turn 1: Player casts Midnight Oil
Turn 1: Jahan casts Rain
Turn 2: Player casts Firebolt
Turn 2: Jahan casts Blitzbolt

The former instantly gets you the damage in the same turn whereas the latter will make you vulnerable to being unable to complete the chain in the second turn.