An interesting note about this show is that due to the incredibly large amount of interesting side characters there are bound to be
a few whom gain a following.
- Triana's friend Kim appears in two episodes, one of which she was featured in, the other she had all of a minute of screen time with two lines. May have something to do with her attitude, her potential to become a supervillain, and her possible ships with the boys and Dermott. Fans have been requesting a return ever since, but the creators stated repeatedly that they had no intention of her showing up again and unceremoniously had her Put on a Bus.
- The Grand Galactic Inquisitor only appears in one episode, but proved to be very popular by hammily shouting "IGNORE ME!" after every sentence.
- Dr. Dugong. He brings peace and love, one gentle cuttlefish at a time. A good chunk of fans were quite relieved and happy that he survived the Monarch's Arching.
- Dr. Killinger has only had three major appearances, but is incredibly memorable, probably because he's basically the Mary Poppins of Evil, seemingly a very helpful and friendly dude, and one hell of a Magnificent Bastard to boot.
- Warriana is starting to get popular because she's an Affectionate Parody of Wonder Woman and because of her growing relationship with Brock.
- Shore-Leave started out as a shallow Village People joke in a flashback. But across more appearances, his endearing utterly camp personality, snarkiness, combined with his complete badassery that almost puts him to be on the same level as Brock morphed him into a quick fan favorite, and Sixth Ranger. It’s to the point that some straight male and female fans have admitted to being attracted to him.
- Despite only one appearance in Season 6, the fanbase adores Red Death. His happy home life, affable nature and ability to go full on nightmare Game Face endeared him to viewers almost instantly. And of course being voiced by Clancy Brown helped. He went on to make several appearances in Season 7.
- The Groovy Gang, a group of minor antagonists who only appeared in a major role in one episode. They were a dark parody of Mystery Incorporated, with each member being based off of an infamous figure from the 20th century in addition to their Scooby Doo counterpart. Fans generally agree that they had a lot of potential as funny and interesting recurring villains, but they are quickly dispatched by Brock Sampson before the end of the episode. However, Ted and Sonny are seen again later as zombies as part of Venturestein's army.
- Henchman #1. He teams up with agents 21 and 24 for one episode, and the audience loved how he was completely competent and professional in contrast to the duo. He spends the entire episode arguing with them about how he's not going to die to Brock Sampson. And then he dies to Brock Sampson... a whole 3 seasons later! Making him one of the few badasses that survived his first encounter with Brock.
- Brick Frog, for the virtue of being an ordinary guy dressed in a frog costume, who's entire shtick appears to just be throwing bricks at people.
- General Triester, because he's an awesome Boisterous Bruiser with the voice of Cotton Hill.
- Scare Bear is one as well despite just (seemly) being a normal, silent serial killer in a blooded bear costume with a knife. He appears in a brief, but memorable scene where he scares the absolute crap out of Phantom Limb, Doctor Incorrigible, and Baron Underbeit by just mysteriously wandering his way into the Revenge Society's interview session. He then briefly appears in a Blink-and-You-Miss-It scene with the Legion of Doom expy. Then saves Hank's life and reveals that Dean has been having sex with Hank's girlfriend. All the while he just stands around and breaths heavily. Fans are clamoring that he and Brock have a fight despite them (seemly) having no reason to fight each other. One theory is that he's a future version of Hank who became a supervillain and that he ensured his own turn to evil by showing his past self that his girlfriend cheated on him. Amusing, but still just a theory. Another theory is that Scare Bear is actually Hank and Dean's Missing Mom, Bobbi Saint Simone.
