marx (kirby)
The main antagonist and final boss in Kirby Super Star and its remake, Kirby Super Star Ultra. Marx tricked Kirby into finding Galactic Nova so he could make his wish to have ultimate power and take over Popstar. After this, Marx turns into his true form. After his defeat, he returns in The True Arena as Marx Soul, the last of the Final Four in said sub-game.
He makes a return in Kirby Star Allies as a Dream Friend. He is part of the first wave of post-launch Dream Friends alongside Rick, Kine, Coo, and Gooey.
He also appears as a boss in Super Smash Bros. Ultimate.