My first ever MC named Endro (now named Yuto Hoshino) who has gone through several reboots, and the last being my Xenoverse Cac also named Ash (now I'm still workshopping him and his story). I've always let my cringe mistakes from him help to balance and flesh out more characters so in a way he's-

Had an enormous impact on my writing and is the reason I have over 2,000 ocs for so much stuff I can barely keep track of it all! I might bring him back as a "Movie" type villain for all three ocs to fight, showing how far I've come from a power fantasty writing kid to a "good" writer.