Champions are a category of boss-like monsters that can be fought after The Phantom is defeated. Champions are not final bosses, Just bonus adversaries that the player can challenge themselves with after completing The End. Champions drop large amounts of money on death, along with a unique trophy/plaque/banner/etc.. Sometimes, they drop other things like vanity sets, decorations, or weapons and armors (none of these more powerful than the gear obtained in The End).
To fight a champion, the player must first speak with the Herald who sometimes appears at the player's spawn point. When a Champion dies, a message appears saying "(name of champion) has been vanquished!". The Champion's drops will then fall on the ground, and the champion itself will fade away.