Ankoku Shindenshou Takegami

Huge monsters of mystical origin fight against each other. The monsters joint forces with young men. A girl is in love with one of them. Between the fights is a lot of talk. 

demons/gods take possession of people causing a scramble in town, in that the main chara needs to fight on to save the world with magical/spiritual powers. 

Guardian of Darkness and Cybernetics Guardian are action-packed anime, filled with violence and blood from the early 1990's. They are stylistically similar by having our main character transforming into a powerful armor being that fights with special psychic powers. Both have a similar animation style and atmosphere. If you like, you should like the other. 

Both the 1970's Devilman TV series and Guardian of Darkness follow a protagonist who has a demon inside a human body. Both anime are action-packed and have the main character able to grow bigger to fight other giant monsters that are constantly attacking other people. They both must protect a female love interest (Miki in Devilman and Terumi in Guardian of Darkness). If you like, you should like the other. 

The main characters of both series fight against evil monsters that are constantly attacking and only the main characters have any chance against them. Both main characters fight monsters by transforming into a super powerful armored being and must protect the humans that they encounter. Differences between the two are that Tekkaman Blade is sci-fi while Guardian of Darkness is a dark supernatural anime. If you like, you should like the other. 

In both anime, the main protagonist has access to an armor that grants them supernatural abilities. The main protagonist in both titles must save the world from evil demons. Both are dark action-packed anime with violence and blood. They both have a tokusatsu feel to them. If you like one, you should like the other.