Arifureta Shokugyou de Sekai Saikyou 2nd Season

Synopsis

Eri reveals that she sided with the demons and used her necromancy to have the knights killed and turned into undead under her control. She also assumes that her main objective is to turn Kouki, with whom she is in love, into an undead as well so she can have him all to herself. Kaori and Lilliana arrive to help and Kaori uses her powers to heal the rest of the classmates, who begin to fight back. That is until Daisuke mortally wounds Kaori, so that Eri can turn her into an undead and he can have her by his side. But suddenly Hajime appears to stop them and after slaying all the knights, Hajime is about to kill Eri when Daisuke attacks him. Hajime then throws Daisuke to the outskirts of the colosseum where he is devoured by the monsters. Freid arrives and challenges Hajime to defeat the thousands of monsters invading the city, which he easily does with a space weapon developed by him. Eri takes the opportunity to escape with Freid and Hajime's party take Kaori's body, having a plan in mind to fully resurrect her.

(Source: Wikipedia)