Posting up my idea, will complete the character sheet later in the week...
Professor von Karstein is a mutagen-focused alchemist, geared toward being effective in melee. He befriended Professor Lorrimor a decade ago, when Petros was a visiting lecturer for a term at the University in Karcau (assuming there is such a thing, I'm ad libbing a bit). Andreas was the professor of Anatomy and Physiology there, and the two hit it off and became fast friends during Petros' time there.
In the years since, Andreas has changed considerably (not necessarily for the better), as his experiments into anatomy have changed and taken a more macabre twist. Indeed, the professor has recently been fired from his post for questionable ethical decisions, and he is living in a flophouse on the streets of Karcau when he receives word of his former friend's passing.
Definitely going for a Jekyll and Hyde influenced character, no secrets there. The mild-mannered professor becomes something...different...when he 'mutagens up' for battle.
These are just rough ideas, and written quickly. Much more to come, but I would value any feedback from the DM.