King Dedede appears in nearly every Kirby game, save for Kirby and the Amazing Mirror. While he is usually Kirby's opponent, he sometimes has been known to help him, like in Kirby Triple Deluxe.
King Dedede is the gluttonous king of Dream Land, just as he is in canon. He has kidnapped Jane multiple times, but every time that happens, she's saved by Kirby without a scratch. Dedede also killed Sarex.
However, King Dedede personally has a soft-side for Kirby, and deep down he admires him. In Kirby and the Time Tassle King Dedede steals Kirby's lunch and Kirby chases him. He makes a very minor role in the game, however he does appear in the mini-game Food Wars.
King Dedede appears as one of the starter characters. He can use his hammer to attack but is slow. He has 7 health bars and 4 air puffs.