Count down the anime characters who can best kill Korosensei and see who they are

Tatsuya Shiba

Yakumo Purple

Flandre Scarlet

Two rituals (no special knife required) If you do, you can paralyze Koro-sensei once)

Return to Izayoi

Those who have the "Avesta" Simulation Star Chart

Cu Chulainn ( Spear that pierces the death thorn)

Haruhi Suzumiya

Crow's "Sleep" card (although I don't think Sakura can play the killer)

"Weiyuan" "Material"

Jiubiao Danxi (the coordinates are moving and it is difficult to guard against it)

Yu Xiaomijiu (the voice can be controlled)