Marx first appears as a small, round being about Kirby's height. He has large eyes, brown shoes , wears a jester hat, and typically stands on a ball. After gaining the ultimate power,he gains two golden wings. Instead of having feathers or skin on them, they have glittering hexagonal shapes. .
For years Marx had had a pipe dream of one day taking over Pop Star. At the beginning of Milky Way Wishes, Marx confronts Kirby, fully implying that he wishes to help the pink puffball protagonist, stating his desire that the moon and sun will someday be in harmony of one another, seeing that the two have been recently fighting. Ultimately, Marx tells Kirby he must activate the Fountain of Dreams on other worlds to make the wish granting comet NOVA appear He does so, though rather than asking that the moon and sun make peace, he asks for the ultimate power in order to take over Dream Land.
Kirby Super Star
Kirby fights Marx as the final boss. Unlike some other final bosses in the Kirby series, Kirby is free to use copy abilities instead of just an ultimate weapon.
Kirby Super Star Ultra
In the remake, Kirby Super Star Ultra, Marx replays his roles from the original game, but with a little more. In The TRUE Arena, he appears in a more powerful form, Marx Soul. All his attacks are more powerful and when Kirby defeats him he lets out a horrible scream.
Kirby Star Allies
In Kirby Star Allies, Marx returns in the first update. He's in his first form, but he uses some attributes from his second, like the wings randomly sprouting.
Kirby Super Star Ultra pause screen
"Marx has shown his true form! Fly in and protect Pop Star! Do it, Kirby, our Super Star!"