Episode 44

Happy Birthday Time is the twenty-second episode of Season 2 and the forty-third episode of the Assassination Classroom anime. It premiered in Japan on June 9, 2016.

Summary
After taking out the army unit stationed inside the mountain, Class 3-E reunite with Korosensei. Their celebrations, including a happy birthday to mark another anniversary of Korosensei and Ms Yukimura meeting for the first time, are brutally cut short by the arrival of Yanagisawa and the second God of Death, now a tentacled monster. The pair then battle Korosensei with the students unable to help.

Anime and Manga differences

 * The anime replaces Craig Houjou and his Wolfpack group with an elite SDF (Self-Defense Force) commander and his battalion of soldiers.
 * Class E's Super Gym Clothes camouflage matche with the mountain environment and darkness while in the manga their Super Gym Clothes camouflage was entirely black to match with the darkness.
 * Because the Wolfpack did not appear, Karasuma never gave any intel in the anime unlike in the manga where he gives false information to the Wolfpack.

Trivia

 * An Elite SDF Commander was modelled after Kazutaka Shindo, Kunugigaoka's Baseball Captain.