Chiyu Mahou no Machigatta Tsukaikata: Senjou wo Kakeru Kaifuku Youin - Vol. 8 Ch. 38

[someunregpunk]

oh so the previous hero didn't want to kill the evil dragon and instead used the dagger to put it to sleep. Exactly what a goody two shoes hero would do.

 

[Nova_Aren]

Typical shounen protag feeling bad about taking a life - even if it was literally entirely evil and not even really alive in the first place

 

[Lev9]

predicting that he might be the hero, it will be one of those he travelled in time with healing magic

 

[kamentierr]

You know what, a few chapters ago the book and the demon king mentioned that the previous Hero hates human but loves beasts.

What if the reason that he didn't kill the demon king and the evil dragon is to exact revenge against humanity. So that hundreds of years after he's gone, the demon king and the evil dragon will return and wreak havoc against humans once more.