Beyond Death

In death note why does beyond birthday kill people?

Why is beyond birthday killing people? I thought he was a good person since he was from wammy’s house. Does he do it because he loves the taste of blood? Or does he wanna be like Kira? THIS IS CONFUSING! Someone please help me figure it out.

He wants to prove that he can outsmart L. Beyond Birthday wants to become the criminal that the “great L” can not catch.