Togata was surprised

Mirio is a tall, muscular young man with several visible scars around his forearms. Mirio's design is unique due to his small, bright blue eyes, drawn in a simplistic style with no visible sclera, and his prominently rounder nose than most others. He has blonde hair, the top portion of which is arranged in a swirl of hair, while the bottom section is combed back.

In his school uniform, Mirio dresses like most male students, albeit without a jacket. He wears a belt with a large, rectangular, gold buckle shaped like a carnivorous mouth.

Before becoming a member of the Big 3, Mirio wore his long hair tied in a ponytail. It is assumed that he cut it so that the support department could use it to make him a hero costume that would work in conjunction with his Quirk.

In his hero costume, Mirio wears a tight white T-shirt with the number "1000000" (one million) printed across his chest in a bold yellow font. The trim on the top and shoulder pads are made to match. On his waist, two green lines act as a belt, along with some similar-looking lines on his shoulders, which dip in places to form two Vs. Mirio also wears baggy dark blue pants, with a white back, split down the middle by blue, and white knee-high boots with yellow soles. He wears a red cape and short, thick gloves of the same color. Mirio's costume is completed by a white visor with yellow lenses, though he does not wear it often, as it falls off when he activates his Quirk.

By the time of the Final War, Mirio has made minor adjustments to his suit. It has more yellow piping on the front, and his belt has a slight change, along with a pouch on the back. There are now white lines on the side of his pants, accompanied by different white knee-high boots with white soles. The gloves are slightly longer, and he apparently no longer wears his visor. Eight years after the Final War, Mirio's hair has grown longer, having been shaved on the sides and is now styled into a comically long, spiraling pompadour. His current suit has a different bodysuit, with the top now reduced to a white chest plate with his '1000000' seal printed on it. His gloves are now lighter and longer, with an angular pattern at the end. His boots are now part of his suit, with the soles decorated with a track pattern resembling multiple 'zeros', and snaking upwards and tapering to a 'one' design that ends at the top of his thighs. Her belt is now slightly resigned with a more intense V-shape and protectors on the sides of her hips.

Mirio is usually seen as a very goofy and energetic individual with peculiar habits. Based on his personality alone, many wonder how Mirio is one of the top students at UA. Mirio has a very optimistic attitude and can almost always be found smiling. His character is what led Sir Nighteye to believe that he could be the one to replace All Might as the symbol of peace. Mirio is known for his strange sense of humor. His jokes range from corny to childish, and he occasionally makes a fool of himself for the enjoyment of others. One such instance was when he stuck his clothed butt into the bushes like a puppet when introducing Class 1-A to Eri.

Mirio does not let his laid-back nature cloud his judgment or hinder his dreams of becoming a hero. He has proven to be a hard worker, turning a nearly uncontrollable ability into one of the most powerful Quirks in the world. Mirio constantly seeks ways to improve his skills and attempts to work towards his goals by accumulating different experiences to learn from. [8]

When he was a young child, Mirio accidentally fell into a river, but was saved by a pro hero. This event marked his decision to become a hero in order to save others. Knowing that he cannot rescue everyone, Mirio chose the hero name "Lemillion" because he aims to save at least a million people. Despite Mirio's encouraging personality, he can suffer failure like everyone else. He has an excellent understanding of hero protocols and can skillfully control his emotions to see the bigger picture. [1]

Lemillion and Deku acted for the greater good when they decided to allow Eri to leave with Overhaul. However, their failure to rescue her haunted them once they discovered the truth. This regret put a damper on Mirio's usually cheerful personality and burdened him with immense guilt, leading him to vow to never let Eri come to harm again, a promise he would keep no matter what. [9]

Mirio is also extremely brave, and in contrast to his laid-back nature, is experienced in dealing with dangerous people and is not easily scared. He was able to talk to Overhaul in his usual cheerful manner despite knowing about his past as a dangerous member of the yakuza. [1] He also stood ahead of the entire combined hero force during the Shie Hassaikai raid and fought Overhaul, Chronostasis, Deidoro Sakaki, and Shin Nemoto by himself. [10]

In addition to his bravery, Mirio has shown to be confident in his abilities. He knew he could take on the entire Class 1-A to teach them a lesson and was even brave enough to take on four of the Shie Hassaikai members alone. Mirio believes in his strength and always shouts "POWER!" after winning a fight. [8] [10]

Lemillion repeatedly displays the values ​​of a true hero. He risked his life and even sacrificed his Quirk to protect Eri. Despite knowing how it would negatively affect his career, Mirio allowed his Quirk to be destroyed in order to inspire Eri and fulfill his promise to never let her feel pain again. Mirio's bravery allowed Eri to awaken and set the path for heroes to defeat the Yakuza. Lemillion even continued to fight after losing his Quirk and protected Eri from Overhaul. His incredible tenacity made Shin Nemoto question whether he was even human. [11]

Despite losing his Quirk and his mentor after the raid, Mirio remains steadfast in his hopes of becoming a hero. His cheerful personality has not faded, and Sir Nighteye's final words strengthen him. He even turned down Izuku's offer to receive One For All [12] and told Tamaki Amajiki that he was in no rush to regain his powers, meaning that he is fine without a Quirk. [13]

Regaining his power, Mirio was excited to be able to help his allies again and internally thanked Eri for making it possible.