iczer (series)
Three OAVs released in the late 80s and early 90s, created by Hirano Toshihiro. All are set in a sci-fi era where an alien force plots to conquer the Earth, but are stopped by one of their own.
OAVs
The following tags implicate this tag: iczelion, iczer_densetsu, and tatakae!!_iczer-1 (learn more).