Yea none of these guys are from Mario or are plants

when you think about it king k rool is a part of the mario universe because mario and donkey kong know each other and the original "donkey kong" game has mario facing donkey kong. and DK fights king k rool. so yes i guess you could say King K Rool is a mario character

He apart of the universe but not the games

Don't blame me. Blame Bing

Ah yes, my favorite mario piranha plant enemies