Cabbage, how much of his behavior can be chalked up to him just being a Gadfly? (e.g. forgetting Cucumber's age)
Noisemaster, did he recognize The Nightmare Knight's energy was what stopped his plan? Rosemaster's conversation with the Nightmare Knight indicated a growing resentment Noisemaster had with his leader as he felt the Knight was unreliable. Were his final words "So... It's like that" him conceding to another failure, or just disgust at the Knight's sabotage and an epiphany about how they will never truly win?
Fans are divided on Almond; she receives the lion's share of the focus over the ostensible protagonist Cucumber, while being hypercompetent and even her mistakes turn out for the best. Some find her a boring character because of this, while others argue that part of the story is subverting conventional hero roles and she's fulfilling Cucumber's role as the legendary hero. For their part, Gigi considers Almond and Cucumber both the main protagonists, but some still point out that Cucumber still hasn't had much opportunity to step outside of other people's shadows.
There also seems to have been another divide due to Almond getting Cucumber, herself, and Carrot almost killed by Nightmare Knight.
Some fans are shipping Noisemaster with Mettaton, due to their similar personality and Leitmotif.note Toby Fox, creator of Undertale, made a theme for Noisemaster, which he would later reuse to make Mettaton's theme.
Cry for the Devil: When Almond yells at Cucumber for trying to talk to the Nightmare Knight, she says: "It's just a trick!" This makes the Nightmare Knight flashback to a previous legendary hero who says the same thing when the Nightmare Knight attempts to talk to him and his sister, to be given the same reply. It gives a hint that the Nightmare Knight was once more hopeful and amenable to working things out, but the endless cycles of resurrections and heroes has worn him down.
Almost anyone who's ever appeared in a somewhat minor role — Cabbage, Cosmo, Baguette and Tartelette, Grizzlygum, Saturday's butler Brambleby, Liquus, Cap'n Bubblebeard, Crabbro, Lute... the list goes on.
Mr. R managed to capture the hearts and minds of the people before he even uttered a line of dialogue and his popularity seems to only be set to increase with time. And, as it turns out, he's also the above-mentioned Brambleby, making him an Ensemble Dark Horse twice over.
Not to mention his assistant Azalea, who without having a single line of spoken dialogue yet is one of the most popular characters in Chapter 3 because of her design. Her popularity was increased when she was revealed to be the princess of the Flower Kingdom, but skyrocketed when it was revealed that she is Saturday as well.
When they were first introduced, Mr. R's seemingly inconsequential assistants◊ and their buildup into their reveal as the kings of the Flower Kingdom, Aster and Sunflower had made readers increasingly excited to learn more about them.
Quakemaster's long-awaited reveal was met with much hype and praise for his clever design.
Fan Nickname: Sir Carrot (after his armor transformation) is often referred to as Hot Carrot or Bishie Carrot. Even Gigi (jokingly) calls him such in their Twitter comments.
Fourth Wall Myopia: In light of the Princess R competition, Almond has received a lot of hate in certain circles for being antagonistic towards the Nightmare Knight. However, the only one to have seen his softer side thus far is Princess Parfait; additionally, nobody in Cucumber's party knows that the Nightmare Knight who nearly sent them into the sun was most likely a fake. And Almond does have good reason to be legitimately concerned that Cucumber is in danger, since the Disaster Masters want to get rid of the Legendary Hero and the Nightmare Knight is much stronger than he is.
Fridge Brilliance: On paper, Thebestmaster sounds like the perfect henchman to the Nightmare Knight. One is powered by fear, the other makes Psychological Torment Zones. It's not a far stretch to guess that the Nightmare Knight created Thebestmaster first, not Splashmaster.
Princess Piano is named not just for the instrument but also for the musical term which indicates playing softly—it is, of course, an Ironic Name.
Chapter Three is fun for plant nerds. When Carrot and Cucumber infiltrate Rosemaster's later, they find a number of orbs containing flowers and Cucumber points out one that looks like Almond's hair doodads. Carrot has a "Eureka!" Moment when he finds two other odd-looking flowers. The first one is an almond flower. The ones Carrot finds are a cucumber and carrot flower, hinting they have something to do with the people named after them.
In Chapter 3, enough hints were dropped in the story that several readers figured out the exact nature of Rosemaster's memory manipulation before it was explained in the story itself. Consequently, the true identities of King Aster, King Sunflower, and Princess Azalea were deduced some time before The Reveal.
Also relating to Chapter 3, Saturday being the missing Flower Kingdom princess was once a common theory, but mostly forgotten after Azalea's introduction... which is likely how the reveal that Saturday is Azalea went all but unnoticed.
Even though Splashmaster is... well, Splashmaster, it's easy to feel bad for him when he's challenged to a game he doesn't understand and is physically incapable of participating in.
Noisemaster and Mutemaster. Noisemaster was legitimately evil as he tried to kill Nautilus and the entire Melody Kingdom, but his depression after his Near-Villain Victory is sabotaged makes it hard not to feel sorry for him, especially since it's implied he's gone through the same plot beats a hundred times.
LGBT Fanbase: Particularly since several of the most popular characters (Peridot, Rosemaster) are gay, transgender, etc.
Magnificent Bastard: The second and fourth Disaster Masters prove themselves a cut above their siblings:
Noisemaster is a diminutive, one-eyed machine whose DJ persona does well to hide the ruthless and dangerous schemer he truly is. Making a colorful entrance by joyfully hijacking Princess Piano's concert, he reveals his intent to use his Noise Blaster satellite cannon to reduce the Melody Kingdom to ruin. Working together with his pal Mutemaster, Noisemaster stealthily kidnaps Piano and uses her persistent screaming to power up the Blaster. When she catches on to his plans and calms herself down, Noisemaster simply waits for the heroes to arrive, manipulating Cucumber and Almond during the ensuing encounter so that he can isolate and strike Princess Nautilus, pushing the Blaster up to 100% charge with Piano's resultant yelp of horror, nearly winning with ease were it not for the last-second intervention of the Nightmare Knight.
Rosemaster is an elegant and theatrical plant-woman out to seize victory in the Nightmare Knight's name, no matter how many attempts it takes. Using her powers of memory manipulation, Rosemaster concocts an elaborate scheme to trick the heroes into delivering her the power-boosting Hocus Crocus, via erasing all traces of the Flower Kingdom's royal family, setting up a fake contest to obtain the Crocus, and kidnapping anybody her powers don't work on so that they don't interfere with her script. Unfailingly loyal to the Nightmare Knight, when Glitchmaster reveals that he's been sabotaging the Disaster Masters for centuries, Rosemaster feigns anger to string her along, setting fire to Glitchmaster's plot to kill him so she may save the Knight from her wrath. While ultimately victorious and in a position to wipe out the heroes in one swoop, Rosemaster's personal conscience and faith in the Nightmare Knight cause her to throw the fight, praising Sir Carrot for his performance as she disappears.
Misaimed Fandom: In the Rosemaster battle, some fans had the impression that Rosemaster was being open-minded and respecting Almond as The Hero even though she's a girl by singling her out—neglecting to realize that Rosemaster was Just Toying with Them, and the entire sequence was of her ruthlessly terrorizing a child.
Platonic Writing, Romantic Reading: Thesepages led some people to read a romantic subtext between Rosemaster and the Nightmare Knight. Gigi had to tweet a reminder that he was "technically her dad". For this reason, the print version changes one of Rosemaster's lines to say "birthday" instead of "wedding".
Rooting for the Empire: Rosemaster, being a compelling and sympathetic villain with an excellent flair for the dramatic, had more than one fan saying they wanted her to win during the Boss Battle in Chapter 3.
Once Mutemaster Turns Red in the Melody Kingdom and Noisemaster drops his attitude, things get dire fast and the danger from his Kill Sat suddenly feels like a real threat. He triggers its final charge by trying to kill Nautilus. When it fires, the next page is a montage of the terrified citizens they'd all met.
The Rosemaster battle. It starts with her attacking a fellow Disaster Master with an Amplifier Artifact. Then she proceeds to toy with the heroes. Almond is reduced to tears. Then Rosemaster brainwashes her to attack Carrot. And then Carrot gets a major power-up from The Power of Love, but that's still not quite enough to deal with a twice-powerful Rosemaster... Until she takes an attack to the artifact deliberately, to spite Glitchmaster.
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