Оояма Такеру

A perverted high school student. He hates his father believing him to be the reason his mother died. He wields a power known as "blood pointer" which allows him to drain "element" from the people around him through his mouth. He has periodically used this ability throughout the series without knowing it. After the battle with the Venus unit he has begun to undergo training to understand this power and use it. He is the childhood friend of Haruko Ayama. His maken is known as "Overblow", which lets him cause his opponent's maken to gain incredible power and overflow with element causing it to go out of control and force the user to not be able to use it.

However, when his opponent is able to contain the overflow of element or has perfect control over his maken, it would only provide his opponent greater power or even make the maken evolve into something greater. (Source: Wikipedia)