Roprinplup14/Prinplup14 (better known as Enzo) is a major YouTuber and a forgotten character in the SMG4 series.
He was a friend of SMG4 who resided at the castle before turning evil after Mario ruined his birthday.
after Mario accidentally ruined his birthday party, Enzo became an extremely angry and short-tempered individual who focused all of his hate and rage on the plumber, to the point he tried to have SMG3 kill Mario, only to fail.
This caused him to snap and became a full-on psychopath.