Chaos King. The final boss of Deltarune Chapter 1. A Spade King card Darkner. His image color is blue, and his eyes are not visible. He wears a white crown on his head. He has a cute body that doesn't match his personality—he looks like a hamster. Perhaps realizing his hamster-like appearance, there is a hamster wheel and a water dispenser inside his cell, which he is somewhat satisfied with. He hates and loathes the Lightners who harmed him in the past. Consequently, he harbors hostility toward them. In the past, some Lightner children were playing with cards and damaged the Spade King card; since a deck of cards is useless if even one is damaged, all the playing card Darkners became unusable. From King's perspective, it was as if the Lightners suddenly mutilated him and rendered his people useless. This is why he remains locked in the Castle Town dungeon even after losing to the Fun Gang in Chapter 1. His favorite food is cashews, so you bring some every time you visit the cell. He has never abandoned his desire for revenge against the Lightners who discarded him. His son is Lancer, a Spade Jack card Darkner. Lancer is very innocent and childish, a mischievous "villain-to-be" who wants to follow in his father's footsteps (though he is actually very pure and kind). King does show concern for his son, such as asking about his well-being. Rouxls Kaard is a Rule card Darkner who, despite his elegant appearance and speech, is frivolous and arrogant. King is Rouxls Kaard's former boss, and Rouxls is Lancer's godfather (Lancer calls him "Lesser Dad"). Male. He doesn't have a great relationship with the Fun Gang. If you look closely, he's a bit pitiful, rotting away in a cell alone. Despite his name being King, he doesn't use overly regal or archaic speech patterns.

A Darkner who is the personification of the Spade Jack card. He is still young and a (self-proclaimed) villain-to-be. Unlike his father, he is friendly—even incredibly close—with the Lightners. He often rides his bicycle around, thankfully using his horn to stay safe. He looks very similar to King, enough to be mistaken for a younger version of him (in appearance only). He seems to like Rouxls more than King, and when he's sad, he likes to be bounced like a ball. Because of this, you bounce him like a basketball. He is very short and hamster-like. An unstoppable prankster. Toothpaste hair? Male. He loves making friends and is best friends with Susie (they get along perfectly). He calls Ralsei "Toothpaste Boy." His laugh is "Ho ho ho!" He is very close with the Fun Gang and gets along great with you. Thanks to his unique energy and personality, he fits in anywhere.