A Kirby with entirely pitch-black skin with a dark cloak and a top hat
In the first game, Sickly appears as a boss 5 times, as well as piloting not one but two robots, one as a normal boss and one as a secret boss. He was the main villain.
Wheelzen: Revenge of Sickly
Sickly and Miracle Nebula are both bosses at 2 points in the story, but they are not main villains.