Cape Wings: Curiously averted here, as opposed to his previous appearances; in the opening cutscene, Meta Knight throws off his cape and reveals his wings underneath. Was he wearing a cape on top of a cape?
"Hey, itís everyoneís idol! Don't let the cute fool you! Heís a brave warrior who may be small, but his spear packs a huge wallop!"
— In-game description
Ascended Extra: His first appearance was as an opponent in Kirby Super Star's Megaton Punch. In Super Star Ultra, he appears as King Dedede's personal helper in Revenge of the King. In Kirby's Return to Dream Land, he is now a playable character, aiding Kirby, Meta Knight, and his King.
Badass Normal: Unlike his allies, he has no real abilities in Kirby's Return to Dream Land. In fact, he only wields a spear.
Expy: To Marx. Sets Kirby up to go on a quest, collect stuff important to his plot, in order to obtain great power? Marx did it first. Also, his second form is called Magolor Soul, just like how Marx's is called Marx Soul.
Heel-Face Turn: In Kirby's Dream Collection, Magolor returns and claims to have built a theme park for Kirby as an apology for what he did in Return to Dreamland. While his credibility might be shot at this point, it's worth considering that he might have been possessed during Return, due to his Dark Matter like eye in his final form, and the fact that he has all kinds of chances for foul play during Dream Collection, but never does anything more malicious than attack him to get the lead during his race challenges.
Hidden Depths: After getting all of the energy spheres, Magolor will explain the history of the Lor Starcutter. He mentions that the Lor may have a mind of its own and that he hopes that it will speak to him one day.
He also mentions that he heard of Kirby and the others through a friend, long before he actually met them, and loosely recalls the events of Milky Way Wishes. This has made fans speculate that Magolor's friend was Marx.
Informed Ability: He's the captain of the Lor Starcutter and requires you to find the energy spheres for him, but he never actually repairs the ship. At least not in front of Kirby.
Or maybe he just rebuilds everything while you're away and playing through the levels.
Despite the fact we never see him use any combat abilities outside of his Master Crown forms, Magolor attempted to fight Landia by himself before he enlisted the help of Kirby and his friends. Even though Magolor lost against Landia, it still implies he can fight a bit without the Master Crown.
Non-Indicative Name: Magolor Soul is anything but; it's implied in the pause screen text that you've destroyed the actual Magolor by this point, and what you're fighting is nothing more than the Master Crown's recreation of his body to use as a host to channel its power through. Though there is some remainder of Magolor in there, feeling remorse for his actions.
Ships That Pass In The Night: Due to their common jester-like appearances, Manipulative Bastard tendencies, and similarities in general, Magolor is commonly paired with Marx in fanworks, but there is little to no evidence that the two have ever met, save for one line that he says on board the Lor, stating that he heard about Kirby "from a friend".
The Southpaw: Take a good look when he attacks when you fight him, especially in his first form. He favors his left hand.
Took a Level in Badass: EX Mode turns his second form into a Soul version, which both looks more awesome and is even harder to beat.
The Trickster: By playing the innocent victim, he tricked Kirby and co. into defeating Landia for him so he could take the Master Crown.
Vile Villain, Saccharine Show: As per the series trademark. He isn't nearly as disturbing as other villains in the series, but he wouldn't be out of place in a TalesSeries game in his Master Crown-enhanced forms.
Genre Savvy: Usually if you stand right in front of Whispy Woods, he can't hit you with anything except for apples. When he Turns Red, standing directly in front of him will get you sucked up immediately when he inhales. In EX Mode, he can extend sharp roots from the ground directly in front of him.
Hoist by His Own Petard: He can suprisingly invoke this on Kirby of all characters by inhaling him after powering up.
Oh Crap: Upon being knocked off the platform after his defeat, he strikes a pose but then gets this face when he realizes that he's no longer on solid ground, and thus achieves his cartoon-style Disney Villain Death.
Bonus Boss: HR-D3 is only fightable in Extra Mode and the True Arena.
Development Gag: HR-D3 originally sported a King Dedede theme in the original Gamecube prototype, Kirby's Dream Course, and the Kirby Quest sub-game of Kirby Mass Attack (in that game, it looked like it does in this game, but had King Dedede's Insignia on it and not the one it has in this game) although it looked more like King Dedede in Dream Course. The D3 part of the name is undoubtedly a reference to that.
Expy: HR-D3 shares numerous traits with Kirby 64's boss HR-H.
Metal General has many moves that are similar to Meta-Knight's, possibly making it a sort of mecha-Meta Knight.
Shows Damage: Played with: Metal General flashes small, electronic numbers when hit, indicating how much damage it has taken. Then it's played straight at its halfway mark when it starts to spark and twitch. In EX mode HR-D3 loses armour, and at the very end, its arms, as it takes damage.
Took a Level in Badass: In the regular mode, the Metal General was a regular boss who came in between the tense, climactic fights between the Grand Doomer and Landia. In Extra Mode, not only does he take control of Dedede's Humongous Mecha, but Kirby and his friends cannot directly defeat him. He is only stopped when HR-D3 collapses and explodes, with the Metal General still piloting it. No other boss in the game can boast this.
What Happened to the Mouse?: It is unknown what becomes of Metal General after HR-D3 is beaten, though one could assume that it simply shut down.
Create Your Own Villain: Literally! Well, the Lor hardly counts as a villain since it's just a shipnote Magolor suggests that it might be sapient, but even if it is Magolor is fully controlling it during the fight so it isn't a true villain anyway, just Brainwashed and Crazy. but you did bring back all the pieces to build it with.
Shout-Out: The symbol on the mast looks an awful lot like the Dark Star from Mario and Luigi: Bowser's Inside Story. Even more, in EX mode, it looks like the Dark Star X, the Dark Star's Bonus Boss Palette Swap.
Unexpected Shmup Level: Interesting case here. Most Kirby Shmup levels have you riding/using the item you've assembled during the game in order to fight a foe who has only recently been revealed (Or only recently shown to be an enemy, at least). This fight inverts it, by having you ride on the previous boss and fight against the item you assembled during the game!
Suspiciously Similar Substitute: Though he is a returning character, one can help but wonder if he was mainly added to fill in the Meta Knight type boss role that was left open when Meta was playable in this game.
The Metal General already fights similarly to Meta Knight with a few twists, making people who realize this think the Metal General is his replacement.
Theme Song Power Up: Possibly the biggest Oh Crap moment in the game is when the music stops for a moment then changes to his theme from Kirby Super Star Ultra