Frieren:
>Demons in human shape
>Only mastered to speak in order to fool human
>Eat humans
Still, somehow moralic ambiguus.

Stargate Atlantis:
>Wraith
>Alinens, strange to us but yet biological life
>Somehow, have their own culture and even technology
And the serial makes them the unambiguous evil. The viewer gets even additional information just to make sure, "this motherfuckers are the bad guys".

Why are they like this?