Sennen Darling

1980s: the town of Senni Dani. After a mysterious and violent incident, Ippei Tsukanoma awakens in the laboratory of Giniro Karisome. Ippei is informed he has been transformed into Millennium Darling, a cyborg created with an ancient lost technology. Ippei, Giniro, and their friends come to discover there are other cyborgs out there... but they are nowhere near as friendly! Now, Ippei and Giniro must face agaisnt these dangerous hostile enemies led by Lord Neiron to protect themselves and Sennen Dani. Welcome, Millennium Darling!

(Source: MangaDex)