demon beast
A Demon Beast is an evil creature in the Kirby series' anime created by the evil Nightmare to be sold to customers by his company, the Holy Nightmare Company. Armies of them were sent down to attack and conquer planets in the past, and were challenged by the Star Warriors and Galaxy Soldier Army but felled all of the Star Warriors except for a few lucky souls to survive the war between both factions (among them Meta Knight). The Demon Beasts are known as just monsters in the anime's English dub.
The Demon Beasts are currently sold to King Dedede, who likes buying them to help him make other people's lives as miserable as possible just for the fun of it. In Episode 94 of the anime, it is revealed that not all Demon Beasts start out evil - after creation, the non-evil Demon Beasts go to school to learn how to be mean and scary. They compete with each other in the Demon Beast School to prove themselves the best and therefore be selected for Nightmare's Army.
In Episode 3, it is revealed that one Demon Beast would not obey Nightmare's orders, and that he fears it might turn against him and one day defeat him. Whatever the Demon Beast that would not follow his orders after creation is is unknown, but some people suggest it to be Kirby while others believe it might actually be Meta Knight himself.