Fawful died at the end of Superstar Saga. That was definitely his undead ghost and not just a clone that Cackletta created during the final boss fight. The Shroobs all died at the end of Partners In Time. Nintendo would definitely have Mario commit genocide against an entire sapient species. Midbus died at the end of Bowser's Inside Story. He was frozen, and that's definitely always fatal in Mario games. The Dream Stone Spirit died at the end of Dream Team. Nintendo would definitely have a character permanently killed off entirely offscreen with no fanfare or even acknowledgement.
