Youjuu Kyoushitsu

These two hentai anime are pretty similar in tone and content as they both feature a lot of disturbing tentacle rape scenes. They also have similar art work, music and graphic violence.  

Demon Beast Invasion and Devilman: The Birth are OVAs from the same time period (late 1980s-early 1990s) with similar animation and vibe. In both anime, the Earth was formerly occupied by demons millions of years ago, and they have returned to attack humans. Both titles are action-packed anime with loads of blood, gore, and terrifying demonic monsters. However, Demon Beast Invasion has explicit rape and sex scenes, whereas Devilman does not. If you like one, you should like the other as well.  

Both are based on a manga by Toshio Maeda. Demon Beast Invasion and Urotsukidouji deal with the threat of demons to humanity. Both have a dark and gritty atmosphere and are quite similar in tone and content. They're both action-packed anime with explicit violence, blood, gore, sex, nudity, and tentacle rape sequences. If you like one, you should like the other. 

More from same director.