The father of Tidus in Final Fantasy X, Jecht mostly spends his time wrecking people at blitzball and telling his son that he's a crybaby. His ultimate move, the Sublimely Magnificent Jecht Shot Mark III, is the showiest way to score a goal in the history of any sport. Jecht eventually leaves for Spira and becomes a bit wiser... then gets turned into a giant fish of some sort, raining destruction on the world and eating people.
There is also a user named after him, famously known for immediately posting "You lost, that's what happened." in a topic where someone asked why they couldn't beat the final boss of FFX.