Digital Devil Story: Megami Tensei

Two terrible adaptations of Megami Tensei games, with all the same elements: devils are summoned from computer data, Cerberus is in a large role, protagonist is a paper thin caricature of the normal high school boy, and nothing good about the source material is carried over in the transition to anime. 

Both are Megami Tensei anime and have some relationship with the games. 

Both being based around notable jrpg series and both also focus around supernautral threats fighting with a ya cast and lots of edge in it too. 

Both are about demons facing off against humans while having references to mythology and the occult. 

Both have a character thats willing to commit dark acts and occultic stuff in it too and a dark and edgy kind of feel to it. 

Both have demonic like beings and other occultic elements to it a ya cast and also a dark and broody edgy kind of feel and both were based on not so faithful adaptations of the books. 

These 2 OVAs are from the 80s. They contain the sense of fear that only 80s media could present. Both are really good with show don't tell so the suspense can increase. They are short and have this uneasy feeling watching. Really great if you are into 80s anime. 

Both titles are OVAs from a similar time period (late 1980's-early 1990's) that have similar art and animation. The main characters in both Dark Cat and Digital Devil Story Megami Tensei have very similar looking character designs. They both focus around supernatural monsters that are attacking innocent people and it's up to a special high school student to stop these monsters from taking over the world. They both have a similar dark and gritty tone with violence, blood and nudity. If you like one, you will enjoy the other.  

Both have hell and demon like beings in it and both also share a similar dark and very creepy edgy kind of vibe to it.