A universal level atrocity
Aster saw the now wary expression on the face of the evil spirit and he smirked, naturally he hasn't committed any atrocity, or at least not something that can be considered one from his point of view.
Even if he has killed quite a few opponents, it's not like he has killed a large number of non-cultivators, at the same time he hasn't abused any women or used them as cultivation furnaces.
Which are some of the ways to get stained by the negative emotions of the victims, like those bandits from the Lagrae Stellar System which kidnapped women for the evil sects, for example.
So naturally his murderous aura shouldn't far exceed the one of a being that exists solely to bring calamity to the living, and it is also denied by the heavens blocking the access to the energy path to it.
The origin of that ominously dangerous black mist which is enveloping Aster, treating him as some kind of relative, is the fact that he has completely eliminated the lives of a few people before.