There are many tales of werewolves but fewer tales of a wolf who becomes a man.
Loki was a reasonable "normal" red wolf until Lord Gairon tried to turn him into a man. The experiment succeeded and failed -- both quite spectacularly. Not long afterward Lord Gairon assumed that the unfortunate creature died.
Fueled by a fanatical hatred of humanity, Loki launched a campaign of villainy. But the experiment kept slowly progressing. And it eventually took too much effort to sustain that much wrath. Besides, Loki didn't want to become fully human!
The quest for a cure became his new obsession.