I'm a tad tired of 'redeemable' or 'misunderstood' characters/villains. While it's a technicality, there's a reason/origin justifying why just about anybody winds up doing everything in their life; the question in fiction is, how much of a character's life/backstory do you want to explore to find or show the readers said reasoning?
I'd like to take Handsome Jack from the Borderlands series, my favorite villain of all time. While he's the antagonist Borderlands 2, hell bent on doing everything he can to save Pandora (from itself), he's also arguably the lead in Borderlands: The PreSequel, and the hero you rally behind to help. Eventually, his character evolves to find just about all Pandora's inhabitants to be lowlife scum, unnecessary and easily disposable as a napkin; hell, he pays you to kill yourself at one point! But if you pay attention to the series, you find out why: abandonment by parents, abuse from his Grandmother, loss of his wife because of his daughter's powers, a shit job that almost gets him killed, and various backstabs and betrayals that he may or may not have deserved.
Does all that justify him wanting one of the most powerful weapons in the universe, and turning it on the inhabitants of the planet he's been terrorizing for years? Does it justify the endless genocide and mockery of life? Fuck no, I can't imagine anything would! But it's that twistedness from being a wanna-be hero and turning into a villain that makes his savagery, sins, and irredeemableness so compelling.
On a side note, I literally just finished playing for like the 5th playthrough last week, but to this day I can't figure out just how much he actually cared for the daughter he abused for all her life, or when he stopped caring for her as his child and instead as his thing to help grant him so much power.
