This Broken Wondrous World by Jon Skovron

My fellow monsters," said Moreau. "No longer will we hide in the shadows, cringing, cowardly, hiding our true potential. You see, the humans do not view us as people. We must force them to expand their view of personhood to include us. By any means necessary."

A year ago, Boy, the son of Frankenstein's monster, had never even met a human. Now he's living with his human 'family', the descendants of Dr Frankenstein, in Switzerland. That is, until the maniacal genius Dr Moreau, long ago banished to a remote island for his crimes against humanity, asks for his aid.

Moreau wants Boy to join his army of animal/human hybrid creatures and help him overthrow human society. Boy must choose: side with the twisted doctor and save his fellow monsters, or try to defend the humans who run the planet?

Boy will do anything to save this broken, wondrous world from the war that threatens to split it in two. But how much will he have to give up? And is the world worth saving?"