Go Nagai crossover movie.

Short film series by Takashi Kurihara.

The protagonist genius, Ye Feng, was betrayed and attacked by his senior, and other evildoers, after he refines the Divine Realm pill that would lead him towards Supreme Realm. He managed to fend off and consume the pill, yet finds himself inhabiting the body of his descendant, who bears his name after 500 years later. He pledge to save his current lineage and seeks vengeance, Yefeng embarked on the path of cultivation again, practicing hard and improving while exploring the mystery of the way of heaven.

The students return as school is back in session for the second semester. Following their exploits on the island during summer vacation, Class 3-E continues to sharpen their blades with their sights set on their teacher, the slippery Koro-sensei. They have more to worry about than just their teacher, however, as enemy assassins, both old and new, are out for the increased bounty on the octopus' head. Moreover, their rivals in Class A, as well as Kunugigaoka Junior High's fearsome principal, stand to block Class E from achieving academic excellence. With all of these obstacles opposing them, the group must continue to work together in order to overcome their foes and accomplish their goal of successfully assassinating their teacher. [Written by MAL Rewrite]