Mirai Sasaki

Mirai Sasaki (佐さ々さ木き未み来らい), also known as Sir Nighteye, was a Pro Hero and Mirio Togata's mentor. He was also a former Sidekick and was considered to be the brains of All Might. Sir Nighteye was renowned for being one of the most astute people in the world until his death after the raid on the Shie Hassaikai.

Appearance
Sir Nighteye was a tall, lean-but-muscular man with sharp features. His shiny hair was always worn smoothed down and parted to his left, and was dark green with three yellow streaks towards the front: two on his right, and one on his left. His eyebrows were yellow, matching the rims of his triangular glasses and his bright-yellow, stern-looking eyes. His looks gave off a sense of authority, as he rarely smiled and always appeared to be frowning.

Unusually for a Pro Hero, Nighteye appeared to prefer bland office clothes, wearing a plain white suit with gold buttons, a white dress shirt, and a red tie with white dots. His clothes, however, seem to be quite sturdy, as he used them during battles and they didn't show any sign of damage.

Nighteye was designed with the intention of invoking the stereotypical image of a Japanese man

Personality
Sir Nighteye maintained a stoic presence with a cold and sharp glare, but that's only the side he showed in public. Even with his supposedly intimidating stare, Nighteye greatly valued comedy and actually required people to make him laugh before he recognized them. Nighteye believed that humor and energy were crucial elements for the future of society and punished subordinates that failed to display those qualities.

Nighteye was a big fan of All Might, having watched videos about his accomplishments and keeping several of his collectibles. He was easily able to remember events and details of All Might's heroism from the past. All Might also attempted to shape Nighteye's vision of what a hero was supposed to symbolize: someone who instills fear in the heart of villains through power and hope in the hearts of civilians through good humor. All Might was also a big fan of Nighteye and was impacted greatly by his death.

Though he appeared to be rather cold in some situations, he was very quick to jump to the defense of his sidekicks and anyone who worked under him. He was quick and very open about when he made mistakes and defended other people who had made mistakes under his orders.

Nighteye supposedly feared using his Quirk to a large extent, particularly when it involved foreseeing someone's death, as he formerly believed that once he saw into the future, that future could not be changed. He changed this mindset briefly before his death, when he witnessed Izuku Midoriya defying his Quirk's vision during the Shie Hassaikai Raid.