Marx

Marx is a character from the Kirby series who made his debut as the final boss of the Milky Way Wishes game in Kirby Super Star. He appears as a boss in Super Smash Bros. Ultimate, serving as the final enemy in the Classic Mode runs of Kirby, Rosalina & Luma, and Inkling. Sephiroth also fights Marx in his Classic Mode route, but not as a final boss. He also appears as a boss in the adventure mode, World of Light, where he serves under Dharkon. A Mii hat based on Marx exists in Super Smash Bros. Ultimate, unlockable for 450 G, that Mii Fighters can don.

Prior to his Super Smash Bros. Ultimate appearance, his boss battle theme from Kirby Super Star ("Vs. Marx") appeared in an arranged form in Super Smash Bros. Brawl and Super Smash Bros. for Wii U. It can be played on Halberd. "Vs. Marx" returns in Super Smash Bros. Ultimate, being a selectable music track for any Kirby stage, and is featured in Marx's boss battle (except for in the Classic Mode runs of Rosalina & Luma and Inkling).

Tabuu, the final boss in the Subspace Emissary mode in Super Smash Bros. Brawl, shares a similar moveset to Marx.