A late 80s/early 90s manga
series by a fellow named Yoshiki Takaya. Revolved around three alien units known as 'guyvers' that, when fused with a human would encase him/her with a sort of 'bio-boosted armor' and give them all sorts of fun abilities. A big bad (strange) corporation known as Chronos is out to get ahold of these units, which were once in their possession but got stolen at the beginning of the story. One of the units comes into the possession of a high school student named Sho, who after fusing with it finds himself on the run from Chronos.
The anime version stopped after 12 episodes and had an English dub which have pretty awful voice acting. The manga, however, is still ongoing and has a very interesting storyline.
Two live action movies were made in the US. The first starred Mark Hamill
(yes, the same guy who played Luke Skywalker in Star Wars
) and was pretty cool if a bit on the cheesey side. The second had a much smaller budget and felt like a long, drawn out Power Rangers
episode. Both don't really seem to follow the main storyline in the manga so much.
Ever since James fused with a Guyver unit he has become far too arrogant for anyone to share his company.