Ralsei is a deuteragonist of Deltarune who debuts in SMG4: If Mario was in... Deltarune. Ralsei is a kindhearted Darkner who appears amiable and optimistic towards his teammates.
Ralsei is a short darkner monster who resembles boss monsters from Undertale. He wears a wizard's outfit, complete with pastel-green tints on his clothes and hat. He also has a long magenta scarf wrapped around his neck and dons a pair of green-colored glasses. When taking off his hat, it is revealed his face is quite similar to that of Asriel, with the exception of glasses, pink shaded horns, and pink fur accents.
Ralsei's first appearance was his debut in SMG4: If Mario was in... Deltarune, in the episode, he would meet Mario and later Susie as they ventured through ?????? and into Castle Town where Ralsei resides. Mario who ran into the castle looking for the "Pepsi Fountain" instead found Ralsei who tries to tell them the Prophecy of the Delta Rune, been mistaken as "Pepsi Man". However, Mario falls asleep a few words into the story. After failing to gain Mario's interest, Ralsei is forced to use the power of friendship and unhoods himself. Mario declines as he throws his bed towards Ralsei pushing him out of the scene.
Ralsei later appears in Mario's battle against Susie and Lancer requesting that they stopped fighting. Susie questioning what Ralsei would do prompts Ralsei to start singing which defeats the 3 and finishes the battle. Afterwards, Mario and friends would continue to venture on through the Great Board and encounter a King Round, while Mario tries to tame the checker dog he ends up causing it to grow a mustache from giving it a Mario hat copy. Mario and the party would soon be run into by K. Round, as they grip onto King Round, it crushed and ran over a few enemies and transported the party over to Card Castle where it would jump up the castle walls and crash into the King and fall a few floors that would lead them underneath Card Castle and into Jevil's prison.
During the battle against Jevil, Ralsei attempts to stop his game as Killing was never an answer but was given a Devilsknife to the head instead. After Mario had convinced Jevil to spawn lethal weapons onto the battle field Ralsei was concerned that the weapons would be too dangerous. Mario would cover up the truth by telling Ralsei that they were friendship blasters that make people your friends. Ralsei instantly took a liking to it as he fires the gun into the air. After Jevil refocuses his attention back to his guests he finsd all 3 of them wielding the weapons he spawned and soon defeated.
During the aftermath of the adventure Ralsei appears on top of Card Castle congratulating the party on their whole adventure as Mario and Susie leave Card Castle into the portal that leads them back into the real world.
If Mario was in...