Finally defeated Magusar, 2 times in succesion, and watched both of the endings. I read that there's a 3rd ending if you defeat him before finishing the story, but don't know how it is.
Anyway, all in all I found him suprisingly compelling. Yeah, an immortal evil wizard is not the most original concept, but the very nature of magic in this setting gives his immortality a disturbing quality.
His most interesting, and obvious, aspect was his right side, completely covered in misshapen eyes. All the druids have mutated right arms that more or less mirror their life views and choices. But Magusar's mutation is just so far beyond any of them, and so brutal, that I can't help thinking each of them signify a "loop" he's been through. Both of the endings I've seen showed that these events reoccur time and again, as long as the immortal essence of Magusar lingers in some form. It can obviously signify his power level etc, but the game's riddled with symbolism and considering the everlasting, repeating nature of both the setting and Magusar, this made sense to me more. In each loop he leaves his vessels beyond, and once again exists as the "true" Magusar inside his captor, fully aware of what has transpired again.
Anyway, what say ye?