Kinji Hakari is a third year student in Gege Akutami's Jujutsu Kaisen, first built up in the manga before becoming a fan favourite during the Culling Game arc. His popularity comes from his Domain Expansion, Idle Death Gamble, which recreates a pachinko machine and rewards a jackpot with a surge of cursed energy and near invincibility. Fans shortened that whole risk and reward idea into the phrase always bet on Hakari, and the line spread through edits, gambling memes and anime discussions whenever luck turned in someone's favour.