Shizu

Shizu was the companion of the previous Hero and a Japanese Summoned One. She is also known as the "Explosive Monarch", an A ranked Adventurer of the Freedom Association's Headquarters, and the formal homeroom teacher of the Freedom Academy's S Class students.

She was also the mentor of several excellent pupils whom became important figures of society.

(Source: Tensei Shitara Slime Datta Ken Fandom)