Korosensei

Korosensei would be the fourth fastest anime character. Korosensei is the anti-heroic supporting protagonist of Assassination Classroom and the homeroom teacher of Kunugigaoka Junior High School's Class 3-E. He claimed to be the creator of the permanent full moon. He also stated that he intended to destroy the earth after a year of teaching Class 3-E.

Korosensei was initially introduced as an enthusiastic character who made ridiculous and seemingly common requests despite declaring he would be the cause of the planet's destruction in a year. He was also generally courteous to others and had the ability to flip from stupid and youth to serious on the fly.

Korosensei's extraordinary speed is one of his unique powers. He can travel at amazing speeds, reaching speeds of up to Mach 20. Under extreme pressure, his normally soft and jelly-like head might harden. This strengthened state minimizes wind resistance, allowing him to reach speeds that are beyond human limits.

Because of his incredible speed, Korosensei may seemingly duplicate himself dozens of times via appearance. Not only can each individual after-image perform a task for extended periods of time, but Korosensei's "speed copies”' are all capable of performing wildly different activities both individually and continuously without becoming confused.

Anime: Assassination Classroom
Watch here: https://www.crunchyroll.com/series/GRE59JGX6/assassination-classroom