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He held the rank of Jedi, but the Jedi Council were jealous and didn’t give Anakin what he deserved.
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He saw visions of his wife dying and was willing to do anything to save her, yes, including killing kids. This isn’t evil; this is true love.
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After he became Vader, he found out his wife died.
Justifiable crash-out, to be honest
Born (or sold) a slave, brainwashed by a powerful private institution (with no oversight) into a killing machine following orders, manipulated by an older (undemocratic) monarch at a very young age, killed by his own handler & left for barbecue, rescued/resurecresurrected/kept alive by the magic force of a democratically elected leader.
He wasn’t much of anything, just a product constantly under overwhelming influence of another.