Jevil is a secret boss in the 2018 Indie game Deltarune. He was the former court jester of the Darkners until he met a "strange someone" and started descending into insanity; first he started saying things that didn't completely make sense, then he saw the entire world as a game, so he was locked away by Seam, the first shopkeeper the player encounters in the game. He is the final antagonist of Season 8, serving as the main antagonist of SMG4: If Mario was in... Deltarune.
Jevil is a short, humanoid creature with a round gray face resembling a mask, elfin ears, clown-like eyes with small yellow pupils and black sclerae, and a large smiling mouth with yellow teeth. He has a long, purple tongue which can be seen either when he laughs, or during some of his attacks. He has a purple tail shaped like a capital letter J. He is dressed in a purple shirt, black trousers, a black jacket, green slippers, purple mittens, and a lime green and yellow collar ruff. He wears a purple and black harlequin jester hat with two small yellow bells. His head appears to be connected to his body via a coil spring (akin to that found in a jack-in-the-box ), which is only exposed when attacked.
During the time Jevil turns the whole room into a 3D environment, he uses a 3D model that is doing a fortnite dance instead of his sprite.
Jevil's first (and only) appearance was his debut in SMG4: If Mario was in... Deltarune, in the episode, after Mario and the party has crashed through the roof, Jevil notices that he had some visitors in his cell. Seeing as someone was here, Jevil decides that he wants to play a game. Although both Mario and Susie refused to play for their reasons Jevil commences the game anyways.
He'd then turn the whole room into a 3D battle arena along with transforming the guest into their own models including Susie who was in distraught about her new look. Jevil will then proceed to fortnite dance while attacking the party excluding Lancer. Before Susie could land a hit, Jevil teleports out of the way and behind Ralsei and Mario. As Ralsei was giving his speech on how killing was never an answer, Jevil would strike him in the head with a Devilsknife.
Mario seeing this would turn around and see Jevil dancing in the air while saying "I can do anything". Mario hearing this line begins to question his powers which annoys Jevil as Mario wouldn't stop asking Jevil if he could do anything and asks Jevil if he can spawn dangerous lethal weapons. So to prove to Mario that he can indeed do anything he starts to spawn weapons from the sky that would be used against him soon.
As Jevil refocuses his attention back to the game he is greeted with the gang wielding the weapons he spawned, After the blast ends Jevil is seen lying on the ground announcing that he has died.
- Anything: A part of being based on the Joker card means that he is able to overpower any other card played such as the King and Queen card. While not canon to Deltarune, it may have other powers only avaliable in SMG4.
- Weapon Creation: Stemming off from Anything, Jevil is able to spawn multiple weapons onto the battlefield from nothing.
- Levitation: Jevil is shown to be able to levitate while fighting the party. Jevil can also hover in place which allowed him to bait Susie into slamming into the battle arena spike.
- Teleportation: Jevil teleports to random spots in the battle arena. This power is only used in his attack "CHAOS, CHAOS, CATCH ME IF YOU CAN!".
- Devilsknife: The Devilsknife is one of Jevil's available weapons used to strike Ralsei in the video. The model used in the video is different from the one found in Deltarune.