During every episode that Dedede Academy appears in, a monster is always there to occupy the school. Basically, the academy's purpose is to teach the Cappy children their lessons. Like any school, it also has rules (with the #1 rule of respecting its owner, builder, and formerly principal, Dedede himself), though the rules are not like any normal school. The school was built and rebuilt on at least three different occasions throughout the series, but naturally, in the end, it was blown up every time by Kirby whenever he destroyed the monster occupying the school.
There are three reasons why it was built; in eNeMeE Elementary, teachers were hired by Dedede and always wore a magic hat on their heads (which was actually Teacher Creature in disguise). The hat turned them evil and they would be mean to their students, giving them overly-complicated problems to solve, punishing anyone who wouldn't follow the rules and giving out lots of homework that no one would be able to finish by the end of the day. In The School Scam, Tiff was hired to attempt to tame Dirk, Kirk, and Smirk through her teaching, which she eventually failed to do, as did all the other teachers hired by Dedede. The three bullies had fun causing trouble at the school until they were humiliated and insulted by Tiff in front of the whole classroom by her beating them up (As they had literally asked for it, and Tiff ended up regretting the decision afterwards). Thankfully, the third and last reason the school was built was a good reason; in Teacher's Threat, this time, the academy was occupied by Mr. Chip (who, unbeknownst to everyone, was in contract with Nightmare). Mr. Chip was so nice and helpful that everyone, especially Tiff, was very fond of him, and he would rather help those who didn't follow the rules with encouragement than punish them. Since he could not do anything to hurt his students, Dedede set Nekketsu on the whole school and he caused trouble for everyone, especially Mr. Chip, until Kirby destroyed the monster and took out the academy with him.
We'll take care of all the details for you, D-Man! eNeMeE Academy is a first-class facility with a super-strict curriculum. We'll whip those kids into shape in no time.”
Hi! I'd like to welcome you to the Dedede Academy. Cappy Town's best - scratch that - only educational institution, where children will learn the three Ds: Discipline, Discipline, and Discipline. You'll receive a handy coupon for the purchase of textbooks, notebooks, and some snazzy up-to-the-minute pencil holders!”
A while back, we celebrated the inauguration of Dream Land's first school: the Dedede Academy. It was dedicated to the noble cause of making all the kiddies behave right. With a little help from Nightmare Enterprises, the school was up and runnin', with lots of classic classes like: how to pitch a pipsqueak, and advanced sledge-hammin'. Things really got rollin' once we got our schoolyard set up. Them brats had loads of fun when I combined gym and detention into one theory. But it all blew up in my face, thanks to that killjoy, Kirby! No matter what I do, that little pink runt wrecks everything! *cries*”
Escargoon, I done founded not one but two schools here in Cappy Town! They was phony schools, of course, set up to get rid of Kirby. Well, even though I deserved an A for effort, every time I tried to teach that pink fake a lesson, I failed. Them schools was a great idea, but for some reason, they didn't do the job. Kirby's still kickin'! *cries*”