Devilman: Tanjou-hen, Blassreiter Recommendations
Both anime involve the main protagonist that can transform into a powerful monster humanoid being that must fight against monsters that threatens humanity. The main protagonist both in Blassreiter and Devilman have to struggle to control their inner demon while trying to keep their humanity intact. They are also both action-packed anime with lots of blood and violence. If you like one, you will enjoy the other.