Leda

Leda is a robot created alongside Dio and Casshern in order to revoltionalize Robotic life through pro creation. This ultimately failed causing Dio and Casshern to become killing machines while Leda stayed behind and took revenge on her creators. Once Casshern murdered Luna causing the Ruin to begin, Leda reunited with Dio as they survived its effects until Casshern reappeared. At this point, Leda began to manipulate Dio in order to gain her desires to rule the world and become truely beautiful. She was able to create an entire army through Dio's obsession to defeat Casshern and eventually track down the reborn Luna. Because Leda did not share in Dio's passion to defeat Casshern, they seperated leaving Leda to deal with Luna alone. She planned to use Luna to end the Ruin and reshape the world in her image. This failed, Luna betrayed Leda and turned her into an ugly machine and fatally wounded her after granting her eternal life. When all seemed lost, Dio wished for Leda to live on after his death, allowing her to die peacefully alongside him. (Source: Casshan Wiki)