Valgaav begin his life as Val Agares, an Ancient Dragon, he watched helplessly as the systematic slaughter of his race. The Ancient Dragons possessed great power, they were feared for their potential to bring chaos into the world, and were destroyed for it by the Golden Dragons. Val, hunted and wounded, fled for his life as his people die by the hands of the Golden Dragons. Val Agares stumbled into Chaos Dragon Gaav the Dark Lord who had recently gone renegade. Gaav, amused at the situation, sensed an opportunity. He wasted little time in destroying Val, and recreating him as a Mazoku renaming him Valgaav. With Gaav's demonic powers flowing through him, Valgaav became strong once more and like all Mazoku servants, blindly loyal to his new Lord. After hearing Gaav death by the hands of Lina Inverse, He seek revenge for his fallen master by killing Lina and her friends.
There is a gentler side to Valgaav. He shows surprising kindness to both Gravos and Jillas and earns their unending devotion for it. Even in the depths of his deepest rage he's capable of rational, reasoned conversations, and he also shows some hints of mercy toward Filia. Much of his violence really stems from despair. Everything he ever cared about was mercilessly obliterated, and he feels himself to be utterly spoiled. So he rages. Ultimately, though, it may be his own destruction that he truly wants as he seeks to wipe the world away