@GenkaiGiven the setting, I don't think I'll be able to fully escape a trope or two.
The gist is this:
He's on good terms with a rather reclusive witch, who imparted to him some of her more esoteric knowledge. Using what little he knew of the arcane, he tried to concoct an alchemical brew which could enhance a Wolkskins' transformation--something to give them a competitive edge should their territory be invaded. Ideally it would have allowed a Wolfskin to maintain its transformed state for much longer, using finely ground beaststones and potent herbs as key ingredients. With no willing test subjects, he tried it on himself. While it was a marginal success, naturally, the experiment had unintended side-effects. Brigh was trapped in a form half-way between beast and man.
Following that incident, he turned to more scholarly studies, becoming something of an expert in alchemy and arcane lore. He has tried many times to reverse the effects over the years, but to no avail.