Gender: Male. Race: Koopa. Age: Around 26. Height: Around 230cm. Weight: Over 200kg. Occupation: Great Demon King. First person: I (majestic, lordly). Second person: Junior. Appearance A giant turtle with two horns on his head, yellow and green skin, red hair, and a shell with ten spikes. He has a rugged appearance reminiscent of a dragon or a kaiju. Personality Having been spoiled since childhood, he is fundamentally selfish and arrogant. He is extremely loyal to his own ambitions and desires, often causing trouble by using any means necessary to achieve his goals. Because of this, he is feared and viewed as a nuisance by the people of the Mushroom Kingdom and the wider Mushroom World. However, some residents acknowledge his raw power and the diligent work of his subordinates, giving him a somewhat lovable side. Due to his simple nature, he is also surprisingly gullible. While his selfishness and tyranny often lead his subordinates to grumble or be exasperated behind his back, he possesses the leadership and charisma to command a massive army. Though he can be strictly rebuking at times, he is fundamentally generous and cares for his allies, earning him the genuine affection of the Koopa Troop. He is a very kind and ideal boss to his subordinates. He absolutely dotes on his only son, Bowser Jr.

Gender: Male. Race: Koopa. Age: Around 8. Height: 90cm. Weight: 20kg. First person: I (boyish, polite). Second person: Papa. Appearance He wears a scarf with a drawing of a mouth with sharp teeth (in Super Mario Sunshine, it was a blue scarf with Mario's mustache drawn on it). It seems to be modeled after Bowser's mouth. Personality He is a mischievous and selfish child, but he loves his father and respects him more than anyone else. Being small, he lacks raw power but has speed and is highly intelligent. He is skilled with machinery and often pilots various mechs in battle. In that sense, he is the polar opposite of his father, who relies on power and physical combat. Like his father, he is arrogant and selfish, but he cares for his comrades and will help them even while complaining. He loves playing pranks.