I feel like Aatrox is very heavily Misunderstood
When his rework just came out people complained a lot that he was just a bucketlist of Edgy101. But I think that his character is a lot more complex than that.
My theory is that Aatrox actually believes he is evil because to him it would be what makes sense in connection to his fate. The way I see it, Aatrox thinks that only if he is evil does his Pain and Misery seem deserving and so he tries to live up to this Idea of being pure and gory evil because he still holds high hopes for the Gods he fought for. It is easier for him to blame himself than to actually accept that his fate was their fault which really shows how loyal he must have been (And probably still is) to Targon despite the way he interacts with their aspects.
And because of that he also keeps looking for fight and death everywhere because he seeks the one person to End this "Big Evil" That he believes he represents. He believes that if he is truly evil that either he deserves the ultimate solitude and guilt by succeeding in being this Evil or that he will meet a force of good that outweights him and kills him, granting him either the punishment he thinks he rightfully deserves or peace of his mind respectively. He doesn't care how things end as long as they do end but he does care about who he believes he is in this world.
I mean at the end of the day, it is just my personal Thesis on who Aatrox is, but It certainly would connect the fragments of his personality into one full circle because just claiming he is edgy101 leaves his personality to be counter-interactive to it's own singular traits which would be bad and make little sense.