Melvin Voyager

An escaped fugitive and alchemist who claims to be Julia's long-lost brother Ashleigh. He uses the same form of alchemy Julia practices, which he uses to crystallize water into snow.

[Spoiler] He is revealed later in the film to be an impostor named Atlas, a former guard of the Crichton family, who murdered Julia and the real Ashleigh's parents and disguised himself as Ashleigh by grafting his face onto his own. He serves as the film's primary antagonist, using Julia to help create a Philosopher's Stone so he can keep it for himself. He is killed at the film's climax by the real Ashley. [/Spoiler]

(Source: Wikipedia)