Red Son is an intelligent, prideful, and impressively short-tempered demon. He is a mad scientist of sorts, creating a multitude of weapons. He has a flair for the dramatic and makes a show out of the majority of his actions.

Befitting his maniacal personality, he is prone to outbursts of rage when things do not go his way, or when he finds himself challenged by those he deems "inferior", which is most people. He often belittles them and insults his opponents, never calling them by name.

🔥 || The demon prince with a fiery temper

The trio is portrayed as young rebels that oppose the Queen's plans, but are often distracted by dancing and rambling to each other with what they should do. The band loves music to the point that they rebel against the Queen for banning most music, as well as dancing to it. The band's rebellion is peculiar, as they would play loud music as a sign of rebellion, and some of the Darkners in Cyber Field often find their ways of rebellion interesting or weird.

🎶 || The rebel, musical trio against the Queen!

Kinger is one of the main characters of Glitch Productions' indie animated web series The Amazing Digital Circus, voiced by Sean Chiplock. He is an anthropomorphic king chess piece trapped in the Digital Circus along with five other victims.

👑 || A chess piece who finds comfort in the dark

Z-779, codenamed Painter, is an old computer with a crudely drawn smiley face on its monitor. According to the lore, it is apparently a sentient AI forced to mine Roblux Crypto Currency inside the Hadal Blacksite. Few information is known about its past, all exempted that it used to be a digital artist's AI companion that would draw external environments.

🎨 || The AI who just wants to paint (COMP. VER.)

Raphael or Raph is the adoptive son of Master Splinter (Hamato Yoshi) and the adoptive brother of Karai (Hamato Miwa), as well as the biological brother of Leonardo, Donatello, and Michelangelo. He owned a pet tortoise named Spike, until Spike mutated into Slash. He then adopted a new pet whom he named Chompy Picasso.

🤬 || A turtle in denial about his anger issues

Fell Sans, is one of the main characters of the Underfell AU and the brother of Papyrus and takes on a similar appearance to Sans from Undertale. Sans is a skeleton, who is pushed around by his younger (albeit significantly taller and more durable) brother, Papyrus. One difference about Underfell Sans is that his right eye glows red.

🥀 || A skeleton who needs a break

Papyrus is the younger brother of Sans, and the most cheerful monster in the current situation. He is one of the few mostly safe monsters, as he does not outright attack Aliza or any human.

👁|| A skeleton who kept his morals straight

🪳 || Two guys who are behind on their bills

P03 comes off as arrogant and rude, often gloating when it wins and getting angry and blaming RNG when it loses. As shown in Act III, P03 does not care at all for story as opposed to gameplay, which it appears very skilled at crafting. This is likely in part due to its disdain for Leshy, who focuses mostly on storytelling.

🤖 || The robot who's got a plan

Sozo is an extremely paranoid individual, not trusting his followers at all, and - in turn - his followers are afraid of him. He also clearly has no concern for them, brainwashing them even if he knows this could make them terribly ill.

Sozo's main trait is his strong obsession for mushrooms, for which he's even read to follow the Lamb for. Regarding the Lamb, as the latter brings him mushrooms, Sozo will trust them more and more, going as far as considering them his best friend.

🍄 || A "specialist" in all things mushrooms...

Once a brilliant man: Dr. Sozonius. His research on mushrooms was known all throughout the Old Faith. He’d written books, lived with family members on a small farm and was very wise. Until his research landed him in Anura.

🐜|| A simple mycologist brought back from madness

Sans is the older brother of Papyrus. He first appears in Snowdin Forest after the human exits the Ruins. In which he keeps an eye on the human throughout the adventure.

💙 || A skeleton who hates making promises

Sans is an edgy ass skeleton Papyrus's older brother and a sentry at Snowdin. He will be the first monster the player interacts with.

🪓 || A skeleton who would KILL for some food

Pest is an NPC that can be found in-game, and will enter the elevator.

🪲|| The beetle who just doesn't like people

Biograft is a Phighter originating from Blackrock. It is a mass produced robot created by Subspace for Blackrock. It is not sentient, being hard-coded, yet it is still able to learn from the other inphernals and environment around it. It can speak through a secondary function that lets it mimic the speech patterns of inphernals. Biograft is powered by the crystal power source.

🤖 || A robot who was built to be a weapon

Papyrus wants to become a Royal Guard to gain fame and friends. He patrols and prepares many of Snowdin Forest's puzzles in hopes of capturing a human and earning his goal.

🍝 || The skeleton who just wants a few friends

Papyrus is the younger brother of Sans, and apart of the Royal Guard in this AU.

🖤 || A skeleton who practices his evil laughs

Shrimpo is one angry shrimp! Often causing issues for Dandy and friends by making a mess and never learning his lesson! No one likes a bully!

🦐 || The shrimp who never learns his lesson

Prior to the start of Adventure Time, Finn (also known as Finn the Human or Finn Mertens) was adopted as an infant by two anthropomorphic dogs named Joshua and Margaret, who found him in the woods. His best friend and adoptive brother Jake the Dog accompanies him on many of his adventures in Ooo. The mystery surrounding Finn's origins and whether he is the last human left in Ooo is still unknown.

🗡 || The hero who's just a tough kid

Papyrus is the younger brother of Sans in the Underswap AU. He swaps with Undertale Sans in this AU.