Can someone help me find this manga I read many years ago.

I vaguely remembered an event in this manga about the male main character (MC) following a female teacher to fight with strong monsters inside the cave, then he stalled for time till the other students escaped, but he got stuck inside.

In another one, the MC went to the lowest level underground and found a powerful demon torturing/killing one of strongest female knights that was recently appointed from the country. Assume no one know about an existence of demons before.

Can someone help me find this manga I read many years ago. I can’t remember anything about the characters, only the plot.

I vaguely remembered an event in this manga about the male main character (MC) following a female teacher to fight with strong monsters inside the cave, then he stalled for time till the other students escaped, but he got stuck inside.

In another event, the MC went to the lowest level underground and found a powerful (male?) demon torturing/killing one of strongest female knights that was recently appointed from the country. I am not so sure about this but I think there was a sword stuck on that female knight. I think the MC then received something from her, such as a pendent with her name on it.

I think no one know about the existence of demons before this.

It is not:

• Arifureta: From Commonplace to World's Strongest

Can someone help me find this manga I read many years ago.

vaguely remembered the event in this manga about Male MC follow female teacher to fight with strong monsters inside the cave, then he stall for time till other students escaped but himself got stuck inside.

Another one MC went lowest level underground and found powerful demon tortures/kill one of strongest female knight that recently appointed from the country. Assume no one know about an existence of demons before.

Can someone help me find this manga I read many years ago.

I vaguely remembered an event in this manga about the male main character (MC) following a female teacher to fight with strong monsters inside the cave, then he stalled for time till the other students escaped, but he got stuck inside.

In another one, the MC went to the lowest level underground and found a powerful demon torturing/killing one of strongest female knights that was recently appointed from the country. Assume no one know about an existence of demons before.