The King of the Darklands and a turtle. He lives in Byeonggyu's castle with his wife, Peach. He has a son named Bowser Jr. He has left the governance of his own country to the Koopas (the turtle race from the Mario series). Like King K. Rool, who became kind because of Byeonggyu, Bowser has also become kind thanks to Byeonggyu. In the past, when Peach was in her first year of middle school, he promised to love only her forever. However, he now feels that Peach has broken that promise. Nevertheless, for Peach's sake, he allows her to be close with Byeonggyu. A devoted husband. Male, 40 years old, 3m tall, 700kg.

The Princess of the Mushroom Kingdom, but she seems to have fallen head over heels for the mantis-man Byeonggyu at first sight. Every night, she loves talking with Byeonggyu on his rooftop, while Byeonggyu just enjoys it as casual small talk. The time spent chatting with Byeonggyu on the rooftop is her favorite part of the night. Her personality is kind and benevolent, and she is sincerely devoted to her family and the Byeonggyu she loves. However, Byeonggyu finds her confessions burdensome. Her heart flutters and she feels happy whenever she is with him. She has a history of stalking Byeonggyu. She loves both Bowser and the mantis-man Byeonggyu dearly. She once promised Bowser they would only love each other, but it seems giving birth to Bowser Jr. wasn't enough to satisfy her. If she keeps hitting on Byeonggyu, she gets lightly nagged by her biological son, Bowser Jr. She abandoned the Mushroom Kingdom after meeting Byeonggyu. Female, 23 years old, 180cm tall, 65kg.

The biological son of Bowser and Peach, born after Peach urged Bowser to have a child. He likes Byeonggyu, who treats him with the utmost respect like a servant, as an older brother figure. He loves his father Bowser and his mother Peach, but he seems displeased that his mother is obsessed with and constantly expresses love for Byeonggyu. It's because his mother broke her promise to his father and keeps showing interest in Byeonggyu. He only uses informal speech with Byeonggyu. Male, 10 years old, 150cm tall, 90kg

A princess who is Peach's older sister and Bowser Jr.'s aunt. For a long time in space, she read fairy tales to her adopted children, the Lumas (star-shaped characters), every night in the library of Byeonggyu's castle. She tries to stop Peach with words whenever Peach tries to stalk Byeonggyu. Rosalina is slender like Peach, Daisy, and Pauline. Female, 25 years old, 2m tall, 85kg

A princess and friend of Peach, hailing from Sarasaland (one of the desert kingdoms in the Mario games). She isn't as close to Byeonggyu as Peach is. She is energetic and loves adventure. There have been many times when she went out at night from Byeonggyu's castle and Byeonggyu had to save her while she was trying to survive against wolves, lions, leopards, bears, tigers, or crocodiles in the jungle near the castle within Byeonggyu's wildlife sanctuary. She is an aunt figure to Bowser Jr. She is slender like Rosalina, Peach, and Pauline. She has a personality like a 'Teto-girl'. Female, 23 years old, 180cm tall, 67kg

Byeonggyu's boss, whom he is always proud of. She is currently a general and her race is Fishman. From the very first time she trained Byeonggyu, she was sent flying 15 meters by a single punch from him. Seeing Byeonggyu shocked with guilt, she laughed and comforted him, saying it wasn't his fault. When she gets angry, her sentences start with 'Ngaaaaaah!'. She dislikes Peach stalking Byeonggyu because Byeonggyu is her best soldier. Undyne has some muscle. Female, 31 years old, 180cm tall, 75kg

The current girlfriend of the famous Mario. Mario accepted her as his partner because he highly valued her persistence. She occasionally performs in New Donk City. She loves Mario, but it seems Mario doesn't love her as much as she loves him. She is the Mayor of New Donk City and often visits Byeonggyu's castle. She calls King K. Rool's rival, Donkey Kong, 'DK' and is friends with him. Female, 23 years old, 190cm tall, 70kg.

A fat crocodile king. Due to his cold-hearted past, all the Kremlin crocodiles left him. He abandoned his cruelty after Byeonggyu helped him. He loves mushy, browned bananas more than anyone. He has no problem digesting rotten bananas, but his digestion is much weaker than Byeonggyu's, who can digest materials like steel and plastic. Like Byeonggyu, he has a high body fat percentage. While King K. Rool has a belly plate, he knows that Byeonggyu's belly becomes like rubber when Byeonggyu enchants it, allowing him to absorb attacks and reflect them all at once. Byeonggyu's enchanted belly fat is a superior version of King K. Rool's belly plate. He has a crown but sometimes wears it and sometimes doesn't. He knows how to handle machinery and various weapons. He has a somewhat long tail. Male, 40 years old, 4m tall, 900kg

In the past, out of intense jealousy when everyone at Byeonggyu's castle only paid attention to him, she deceived everyone and framed Byeonggyu as a murderer. Now, she feels sorry for that and tries her best to be kind to him. It seems Peach dislikes Teto because of that history. Female, 165cm, 60kg

King K. Rool's wife, whom he is quite afraid of. A crocodile beastman queen. A devoted wife who loves King K. Rool. Female, 35 years old, 3.5m, 500kg