I think it was just to set up the kingdom of pansylvania as evil & (possibly) show that they had a hand in originating the Oder (?).
I do agree it was a waste to kill off a bunch of new characters. The author probably should’ve had them be nameless or something.
that man is pure evil if he takes pleasure to kill innocent people or just for "better safe than sorry" cause. but it only will earn tons of enemies to that idiot.
A little heavy handed but man, they're really servicing that foreshadowing of Pensylvania being an overtaken country created by someone like MC by these guy from this world.