Valgarv is an ancient dragon that is turned partly into a Mazoku by the Demon Dragon Gaav.  Valgarv hates the golden dragons and all Mazoku but Gaav those who are his servants.  

He teams up with Arumeis to collect Darkstar's five weapons mostly just to get a shot at taking Lina out.  However as events get more and more out of his control, his hatred takes over and he basically goes berserk and sets out to not only destroy Lina Inverse but the rest of the world along with her.

But near the end, Valgarv seems to be as trapped by his "fate" as everyone else and seems as Lina says once to be "Just trying to find a way to free himself."

A red fox that Valgarv saved from a masacre.  He is totally loyal to Valgarv-sama even if he is a bit of a fool some times.  He even gets to become a good guy at the end.

Sort of a lizard man whose head is far too small for his body.  He is Valgarv's main lacky and usually leads the troops of black lizards with Jiras providing back up.  He is, to put it bluntly, rather stupid.

A being from Darkstar's world who served Vorfeed before Darkstar devoured Vorfeed.  Arumeis seems cruel at first but his true goal is to destroy Darkstar and lose as few lives as possible.  He really has a good heart.

The equivalent of Ruby Eye Shabranigdo from another of the four worlds the Lord of Nightmares created.  He and Vorfeed, the equivalent of Cefied, fought and Darkstar absorbed Vorfeed.  The combined being went berserk and destroyed most of the world in an attempt to purify it.