Piccolo

Piccolo Jr., also known as Ma Junior, is a Namekian and the penultimate offspring and reincarnation of King Piccolo, later becoming the reunification of the Nameless Namekian after fusing with Kami, at which point Goku referred to him as Kamiccolo. Piccolo, along with Kami and King Piccolo, are members of the Dragon Clan, who created the Dragon Balls, according to Grand Elder Guru.

Piccolo has only taught Gohan for a short time, yet he's already established himself as a legendary instructor. After Goku died, he abducted a young Gohan to prepare him for the arrival of Vegeta and Nappa. He didn't hold back when it came to educating him, and he began Gohan's instruction by abandoning the small kid in a wasteland for six months to put his survival abilities to the test. He kept a watch on him to make sure he didn't die, but he mostly left Gohan alone.

Piccolo was transformed through teaching Gohan. Piccolo developed feelings for the young boy and considered him as a son figure. He assisted Gohan in regaining fighting form in Dragon Ball Super and even assisted him and Videl in raising their daughter Pan. No wonder why he is one of the best teacher characters in anime of all time.

Anime: Dragon Ball