Baby Assassins 3

Baby Assassins is an action-comedy franchise following the friendship and lives of teenage hitmen Chisato Sugimoto and Mahiro Fukagawa.
Teenage assassins Mahiro and Chisato visit the coastal city of Miyazaki for a contract and a vacation, but they unexpectedly cross paths with a legendary, bloodthirsty assassin looking to add to his kill count.
Even if I kill you, I won't forget.