10) Old Man Superman
When the Silver Age of Comic Books came along, DC wiped continuity clean and retconned the Golden Age versions of their heroes into a different Earth – Earth-Two, to be exact. Since then, the original characters have occasionally been revisited.
Known as Kal-L, Earth Two’s Superman is an older, wiser counterpart to the regular Superman. The leader of the Justice Society of America, he’s also happily married to Lois Lane and the editor-in-chief of The Daily Star. At least, he was, until he sacrificed himself to save the Multiverse in Infinite Crisis.
What’s significant about Kal-L is that he was the first instance of a Superman from another Earth (even though he was already the original Superman). He also got to play a part in some seminal storylines like Crisis on Infinite Earths and Blackest Night. In recent years, he was rebooted for The New 52 where he became enslaved by Darkseid and took the name Brutaal.