@feha This chapter specifically mentioned time magic two panel before two prominent characters were killed. I bet they will come back one way or another.
@boag if you refer to the assassin from the recent omake, then there is no way they are the same character based on the looks
I think he is just a new introduced character
this ninja maybe not too strong : the demon king and the stoner minister beat the silver dragon in a direct battle , while the ninja beat them with an ambush / surprise attack / sneak attack .