The World's Finest Assassin Gets Reincarnated in Another World as an Aristocrat, Vol. 4 (manga)

Lugh vs. Epona! The power of the hero is finally revealed! Having aced the Royal Knights Academy exams, Lugh is now the classmate of his assassination target, the hero, Epona. But he--s only given a brief moment of peace before being thrown into a mock battle with Epona! With no time to prepare, who will win?