Kirby (the universe's favorite pink hero) was named after John Kirby, a man who aided Nintendo in a lawsuit, claiming that Donkey Kong deprived from the movie King Kong.
Kirby games weren't even supposed to be about Kirby at all! Kirby's character was a placeholder for a character named "Twinkle Popo." Ultimately, the team decided to go with Kirby because, come on, Kirby's awesome.
Oddly, on nearly every Kirby game cover, he looks angry. In Japan, though, he looks neutral or happy. This is thought to account for cultural differences.
Lastly, several Kirby games have world names that create an acronym when combined. For example, in Kirby's Return to Dreamland:
This spells out "CROWNED", which is a reference to the fact that the whole game was for the antagonist, Magolor, to obtain a crown to get ultimate powers. Similarly, in the French game, the worlds spell out "PARFAIT" meaning "perfect" in French (and is also a dessert)
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