[Salaryman Zero]

Yeah, Riderman is a good pick. He really brought a lot to V3 and helped cement it as my favorite Showa series. I guess Shadow Moon's another one I can think of to a lesser extent. He didn't really "redeem" himself but he had a moment of humanity before his death in BLACK RX.

Heisei-wise the Snake Orphnoch comes to mind. He starts off really douchey but as they reveal his backstory and develop the character, he became one of my favorites. I guess his redemption started when he turned his back on Kaiba.