Kris Dreemurr is a human Lightner and the main protagonist of Deltarune. They are presumably the human Hero of Light in the Prophecy. In a Dark World, they function as the party's leader. Kris is controlled by the player for the majority of the game. The few exceptions are brief cutscenes or when they tear the SOUL out of their body. Kris excels at ACTing in battles, and wields a sword.

Susie is a Lightner from Hometown and one of the two deuteragonists of Deltarune (alongside Ralsei). She is the monster Hero of Light of the Legend of Deltarune. She wields an axe while in a Dark World. With her high HP and Attack, she plays the role of the party's tank and bruiser during encounters. As of late, she’s become the party’s second healer.

Ralsei is one of the two deuteragonists of Deltarune (alongside Susie). He is a Darkner, claiming to be the "Prince from the Dark" mentioned in the Prophecy. Having weaker attacks and less max health, and with the ability to cast healing spells, he acts as the party's healer. He wields a scarf in combat.

Doesn't speak. The Roaring Knight, or just the Knight (often said in all caps), is the overall main antagonist of Deltarune. They are a mysterious Lightner who has been creating Dark Fountains around Hometown, presumably to summon the Titans and bring forth the Roaring. King, Queen, and Tenna initially align themselves with the Knight, and they may have connections to the strange someone behind Jevil and Spamton's madness. They are the primary foe of the heroes; Kris, Susie, and Ralsei. That said, it is heavily implied that Kris may have some connections to the Knight, and that they may be in league with the town's mayor, Carol Holiday. The Knight debuts in Chapter 3, as the twist final boss. If "defeated,” they drop the Black Shard and a Shadow Crystal.

Flowery (JP: フラウリィ Furaurī) is the leader of the 7 Colored Flowers that composed Asgore and Toriel's wedding bouquet. He is the main antagonist and final boss of Chapter 5 of Deltarune, first appearing in Garden when the party first encounters him.