The Tinkerer & The Droid
The Tinkerer and The Droid are Diablo-esque characters. The Tinkerer is the glass cannon, she starts off with her abilities doing little damage but after she casts consecutive abilities she starts to do more and more damage. The player can also pick "talents" to take as they level up, with each one offering unique tweaks to abilities allowing for different playstyles.
The Droid is the tankier member of the pair and is also an AI companion to the player. He has three modes, which The Tinkerer can assign, these being Medic, Tank and Berserker, each of these grants unique abilities and stats to The Droid.
I've included the design documents below if you're interested in the specific stats and numbers for each of the characters. Aswell as a breakdown of the talents and the abilities.