Assassination.classroom.s02e25.future.time.1080...

It is the perfect echo of a teacher who taught them how to kill him, and in doing so, taught them how to live.

It seems you’ve referenced a file title: — likely an episode of the anime Assassination Classroom (Ansatsu Kyōshitsu). Assassination.Classroom.S02E25.Future.Time.1080...

“Now then, class — let’s begin today’s lesson.” It is the perfect echo of a teacher

That specific episode (Season 2, Episode 25) is titled (or similar, depending on the fansub). It is the series finale of the entire show. and in doing so