Hate Mazoku

Valgarv's hatred explained.

Valgarv's hatred toward the mazoku comes from his nature of being an ancient ryuzoku. As ryuzoku and mazoku are bitter enemies, Valgarv has no love for any mazoku, even though his race chose to be neutral during the Kouma War. Chaos Dragon Garv was the only mazoku that was worth Valgarv's time and even then, Garv was sealed inside a human body and was different from the rest of his kind.

Garv was the only one to come to Valgarv's aid when he was being hunted down by the golden ryuzoku. Neither ryuzoku nor mazoku seemed to care what happened to the ancients despite their neutrality toward the Kouma War. Valgarv felt he owed everything to Garv for saving his life and Garv would be his only true companion for a very long time. Since Garv turned his back on the mazoku, so too did Valgarv. He could never forgive the fact that the mazoku would prefer Garv be dead. His mistrust toward the mazoku would be bolstered by Garv's influence.

Furthermore, Valgarv believes that the mazoku are despicable for not coming to Garv's aid when he was destroyed by Lina Inverse. While the viewers know that Garv was actually killed by Phibrizo, Valgarv believes that it was Lina. Allowing such a powerful former ally to be destroyed by a human leaves a bitter taste in Valgarv's mouth.

Later in the series when Xelloss approaches Valgarv with the offer to join the mazoku, Valgarv believes it's a trick of some kind. Why would he ever join the race that let him and his master suffer? Valgarv is disgusted by the selfishness of the mazoku and promptly declines Xelloss' offer. Xelloss himself says he felt that asking was pointless as he knew Valgarv would never accept. From that point on, Xelloss' express instructions are to murder Valgarv. This effortless change in attitude only furthers Valgarv's hatred toward the mazoku.