Spoilers for Assassination Classroom's ending.

In the final battle,

Kayano is killed, but Koro Sensei manages to repair most of the damage by using the somatic cells he collected from her in the same instant.

Koro Sensei mentions that not all cells can be repaired, so instead he filled the gaps with his mucus and in a few days Kayano's cells should regenerate and replace the mucus on their own.

But this occurs a little before the Heaven's Spear laser strikes, and we know that all the students were hit by it. This would mean that Koro Sensei's mucus would have evaporated, opening the gaps again.

Is there any indication that Kayano's health was affected by the laser strike? Of course I doubt that the gaps would be enough to kill her or cause any major damage anyway, but this seems like a pretty obvious situation to consider.

A possible explanation is that the mucus is unaffected by the laser, but I doubt it because the engineers were complaining that the strike would leave no sample material they could analyze (and I imagine that the mucus counts as sample material).

  • i might remember wrong, but i remember that they killed korosensei before the laser strike was fired
    – Dragon
    Aug 11, 2016 at 11:20

2 Answers 2


Heaven's Spear was only fired once,

and Koro-Sensei dodged it.

During that period, the students were not there. It was never fired again.

After the fight where Kayano was mortally wounded, they killed him after he saved her. The manga basically ends there and there was no more follow-up as it was considered resolved.

The students were never hit with the beam.


First theory: The Spear of Heaven only works on "tentacled" creatures (ep.21). The first time it fired, Koro-Sensei's tentacles disappeared. It is likely that the mucus is dissolved along with the tentacles since is part of the "tentacled" creature.

The story never explains what the tentacles were made of. And not all tentacles do the same things but are made of similar substances (Kayano and Itona vs. Koro-Sensei vs. The Reaper). Mucus and tentacles are two different substances when separated.

Second theory: her human body has already integrated the mucus into her system and made them part of her until the cells can regenerate. The mucus in Kayano is not technically part of a "tentacled" creature but part of her.

Third theory: Koro-Sensei used a special mucus that he normally doesn't secrete.

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