To be honest, I'm not 100% sure who's side the Dark Angels are on. They don't like Ben, one of Drannic's characters for some reason. They apparently have decided to attack the city while they're at it. Or rather, the Tjedians interpreted it as a Dark Empire attack and attacked them. (Heh...)
Melface, Rufo, and Ophelia (currently disguised as wolves) are of the Dark Empire. They are disguised because the Velkens (talking gray foxes, also Dark Empire) kicked them out, and now they are growing suspicious of the Velkens.
The only Lizard Man currently on the island is Lagart, who is a traitor to the Dark Empire and has joined Tjed's side, so he's actually a good guy. All humans are with Tjed, as are Duilin (half demon), Rink (imp), and some others.
Confused yet? Any more questions, just ask!