Assassination Classroom 4 features story and art by Yusei Matsui.

English teacher Irina's assassination mentor makes an appearance and the two compete - using special agent Karasuma as their target. Another transfer student/would-be assassin joins the class, accompanied by a guardian, who claims to be Koro Sensei's... little brother?! A tentacle showdown ensues, sending everyone into a tentacle tizzy. Then, the 3-E students face humiliation yet again during a school baseball exhibition match. Plus, more secrets of Koro Sensei's mysterious past revealed...!