Complex sentence: King Dedede is a large bird that appears similar to a penguin who carries a large wooden mallet as a weapon and is the self-proclaimed king of Dream Land as well as the arch-frenemy (according to the Play Nintendo website) of Kirby.
Split into simpler sentences: King Dedede is a large bird who appears similar to a penguin and carries a large wooden mallet as a weapon. He is the self-proclaimed king of Dream Land and the arch-frenemy (according to the Play Nintendo website) of Kirby.