In Kirby Triple Deluxe, you might wonder what the the Amazing Mirror is doing in the final boss's room. It occurred to me later that Kirby and Meta Knight had to fly up into the sky to get to the mirror, which certainly put the mirror into Sectonia's domain and reach, and because Queen Sectonia is so vain, she has probably been using it as a personal looking glass. The mirror may not be why she's so evil, but it could be one explanation for how she became so monstrously vain.
Throughout most of the Kirby games, Kirby ends up doing things that ultimately wind up freeing or unleashing the Final Bosses. Usually, I just figured that this is because Kirby is too selfish to realize just what his actions do, but after thinking about it, I realized that in most cases, the character he defeats (usually Dedede) takes a morally gray option to avoid the boss, while Kirby has an extreme case of Black and White Morality. In addition, when a player reaches that point for the first time, he only knows about as much as Kirby himself does, and since Kirby sees what Dedede does as a bad thing, so does the player. And since the situation changes at times, Kirby's trusting nature and Genre Blindness prevents him from knowing what evil is hidden just out of sight.
Of course, in the end, Kirby's black-and-white views prevail as the harmful, untrustworthy, or otherwise grey methods to delay the return of the villain fail (with or without Kirby's help), and only the unambiguously good actions of Kirby defeating the monster save the day in the end.
The Kirby series is probably the archetypal Sugar Bowl, a perpetually happy place filled with bright colours and cheerful characters where nothing bad ever happens, the stories merely Excuse Plots for purposes of fun. Except that no, it isn't. Pop Star is constantly assailed by undefeatableEldritch Abominations that corrupt and kill and bring the world to the brink of destruction. The closest thing to an authority figure is a bumbling Authority in Name Only that can barely succeed even in the few times he manages to be competent. The Only Sane Man is a Blood Knight concerned only with combat. And Kirby himself, the protagonist and supposed hero, eats people. Hundreds upon hundreds of people. He is a horrific scale Big Eater on par with the Tyranids, consuming indiscriminately all in his path, and there is nothing anyone can do to stop him.
Keep in mind that most of these "enemies" are completely innocent. Most of them just sit there until Kirby either devours them or destroys their souls.
Also keep in mind he doesn't actually kill them, as you can later spit them out in Super Star.
You know, if Kirby hadn't been around in Episode 39 where Boukyakku made everyone forget who Escargon is, Escargon might have headed to the ocean for a different reason...
In Kirby 64, the True Final Boss, oddly, has a band aid on his head which you have to hit to expose his weak point. It's the reincarnation of Zero from the previous game, so you'd first think that it's a simple call back... then you remember the whole thing where his iris ripped out of the main body...
The creation of most beings in dreamland is through one's heroic heart which is aptly shaped like a star, so what happens when you spit them back out? You are spitting the heart of your enemies or objects.
Kirby's Adventure involves a Nightmare trying to come through the fountain of dreams to hurt the denizens of dream land, for some reason. King Dedede removes and destroys the fountain's power source, which keeps the nightmare on the other side but prevents anyone in Dream Land from dreaming. Kirby fixes the star rod, defeats the nightmare and restores the ability to dream (In case you did not know already) so all is good? Well, in Kirby Super Star it is shown that there are several planets like Pop Star with similar fountains. Another Nightmare could easily come through any of them and neither Kirby nor Dedede can be expected to police them all. Furthermore, the backlash from one Nightmare's defeat was strong enough to nearly destroy Pop Star's moon. At any point, any given bad dream could creep out of any number of places in the cosmos and cause a disaster.
In Kirby's Dreamland 2, Dark Matter comes to Pop Star and makes mischief in Dream Land. Kirby gets a special weapon and defeats it, problem solved? Kirby's Dreamland 3 sees Dark Matter come back and engulf the entire planet of Pop Star. Kirby manages to defeat it with another special weapon, though, and even destroys its supposed controller, Zero. Yet in Kirby 64, Dark Matter successfully conquers another planet and would have been in position to take over many more had Kirby not gotten involved by coincidence. Turns out the controller, Zero, had somehow revived, but Kirby finding another weapon to put back down solved everything, right? No, Dark Matter engulfing two planets as well as forming another one out of its own mass is just a drop in the bucket. At the time of this typing, roughly 80% of the matter in the universe is estimated to be Dark Matter, and with the exception of Gooey, the entire bulk of it seems to be hostile or commanded by a hostile intelligence which has come back from the dead once already in the Kirby series. The worst is yet to come, assuming Dark Matter is not already causing misery far beyond Kirby's area of operation. The fact that Dark Nebula from Squeak Squad was later revealed to be part of Dark Matter shows this plot point has not been forgotten either.