I remembered a design that took me by surprise in terms of "Holy shit, I made that?"
She was from an RP group that focused on characters that were children of - or otherwise created by - two characters from different canons.
In this case, Super Mario RPG and Kirby: Planet Robobot.
Princess Nectarine Morningstar is what happened when the remains of the Access Ark, destroyed by Kirby and the Halberd, fell through a dimensional rift and landed in the Smithy Gang's Factory. Smithy was in the middle of forging a new body for Exor after his failed invasion of the Mushroom Kingdom, but he knew on sight that something about the machinery before him was on par with the accursed Star...Highway? He couldn't be bothered. Either way, he got to work pounding it into shape, deciding Exor could wait just a hair longer. The machine, practically seething with intent despite its inert form, took a new shape influenced by three things; Smithy's contempt for that do-gooder Mario and his lackeys, the residual data of the Access Ark's Mother Computer refusing to be fully reformatted, and scrambled data from a failed overwrite that the Computer attempted on... some kind of external drive. It's hard to recall.
Seeing the magic of a Princess, Smithy decided if he was to be a king, he felt it only appropriate he have a Princess of his own. And given the immense power contained within the machine she was made from, she wouldn't be lacking at all. He would have her hone her skills and abilities, and... little else if she wasn't resting or training. He wanted her to save her power as long as possible for one reason; To grant him his wishes once the time was right.
Morningstar (she didn't hate her first name, but found it too embarrassing) grew sick of it very fast, but her programming as a Machine Made prevented her from lashing out... So it's thankful that it didn't prevent her from leaving once she got the chance. And once she realized she could open the same rifts that her components came from, she took the chance immediately. She briefly stayed in the Mushroom Kingdom out of curiosity, observing its people, but eventually took to wandering the cosmos to truly test her mettle as a super weapon, refusing to take on the mantle of a wish-granter unless that wish was the destruction of those who stood before any prospective allies. All the while, she finds files in her records that tell a complicated story of a computer known as "Star Dream".