The True Legend of the Demon God Urotsukidouji: Connections with the Devil

In 1944, Hitler's inner circle is running a ritual involving something called the Nazi Death Rape Machine to tear open the walls between human reality and the dimensions where man-beasts and demon monsters live. That's the opening scene. It sets the tone pretty clearly. The goal is to summon the Overfiend, a being of terrifying power, and a scientist named Dr. Munhihausen Sr. is the architect of the whole thing. Cut to modern Tokyo, where his son picks up where dad left off, hunting for something strong enough to challenge the Overfiend. He finds a lead in Takeaki Kiryu, a guy who starts developing monstrous abilities after receiving a blood transfusion from his cousin. Meanwhile, a man-beast named Amano Jyaku, his sister Megumi, and their companion Kuroko are trying to stop Munhihausen Jr. before things spiral completely out of control. This is a 2-episode OVA from 1990, part of the Urotsukidoji series, which is one of the foundational works in dark adult anime. It's genuinely horrific in places — graphic, transgressive, and not remotely subtle. If you've seen Wicked City or Demon Beast Invasion, you already have a rough idea of the territory. If you liked La Blue Girl but want something with more apocalyptic weight behind it, this fits. It's not easy viewing, but it's a piece of anime history that shaped an entire subgenre.