Edajima Heihachi
A former Navy Major General turned headmaster of Otokojuku, a brutal school for wayward kids that he's determined to whip into warriors through ruthless kendo training. He's famously stubborn and operates by his own eccentric rulebook—which he'll remind you of at length if you dare question him.
The guy's a legend in his own right: a child prodigy who got into Tokyo University on just a week of studying, then fought hard for the Japanese military during World War II. His character draws heavily from the real-life Admiral Togo Heihachiro, and he's even named after Edajima, the island that once housed the Imperial Japanese Naval Academy.
Best known for his over-the-top catchphrase, which he bellows whenever he's about to finish off an opponent—or basically whenever someone asks him anything: "I AM THE PRINCIPAL OF OTOKOJUKU, EDAJIMA HEIHACHI!!!" It's become his answer to everything, no matter how ridiculous the question.
The character gained unexpected real-world fame when Lee Teng-hui, the former President of Taiwan, famously cosplayed as him.
Heihachi clearly served as the template for Mishima Heihachi from the Tekken franchise—the resemblance is uncanny, from looks and personality right down to sharing the same voice actor in some versions.
Content compiled by AnimeList.moe from publicly available sources.