Tetsu Senshi Musashi

This manga was written and drawn by the great Go Nagai back in 1983. It's about Hanamoto Musashi, a boy who in school, appears to be a nerd, but in reality, he's actually a thug... One day Musashi meets a girl who says she is a Princess of a distant planet. She goes by the name of Princess Yurika. Since then, Musashi's life has been flipped upside down, becoming an Iron Knight with a technologically advanced armor that the Princess Yurika gave to him, that allows him to face her enemies, and avenge his friends who were killed by them! This manga is a clear homage to the historically existed samurai, Miyamoto Musashi, but in Nagai's twisted sci-fi style!