Kyoushoku Soukou Guyver (1989)

Shou and Tetsurou discover an orb-like device in the forest, which fuses with Shou and transforms him into an alien warrior called the Guyver. The Guyver Unit must be protected from Chronos, a Japanese corporation seeking it and two similar units. Chronos deploys Zoanoids, monstrous creatures, to recover the device. Shou's life becomes dangerous, as threats from Chronos and Zoanoids endanger him and those around him.