Lewis
Lewis the.... Frog
History
Early life
Well, that fact the game didn't really reveal. Sorry. If you find something - please, edit this and add it.
Being an alchemist in the Galava Castle
Only that part of his life is known - when Jack arrives to the Tower Of Illusions, he would probably go to all the rooms before meeting Horvath. In one of the rooms, he sees an alchemist named Lewis that is trying to switch bodies with a... frog. He is asking the young wizard to help him in this experiment by pressing a button. He changed bodies with the frog, filled with excitement. Then, he asks Jack to press the button again, because he don't want from somebody to hear how a frog croak in alchemist's room. Jack presses the button, but the bodies switching is not working anymore. Lewis, as a frog, tells him not to tell Horvath about that, while the frog with a mage body going to lolligag a bit in the corridors.
Being a frog
Wizard can later meet him in besieged Brin village. In one of the houses a man gives him a sidequest to save his pet frog from the burning room. After a successful rescue Lewis states that "It ain't easy being green".