This just happened. The thought popped in my mind and wouldn't let go, then it grew and became a headcanon of sorts. I have no idea if this is the beginning of a longer story, or a simple one-shot I won't come back to.
But I do have a playlist for this AU, if yer interested. ( pleer dot com/list2393458UfIF )
And there might be some mistakes in this, because apparently Zane likes to write at 4 AM.

He's got the devil in his eyes, and the curve of his lips screams nothing but ominous as he saunters up to his twin soul. Or maybe they've got one to share, they're still trying to figure it out. Scientifically speaking, it would take to kill one to get an answer to that question, and neither is too keen to check it out. Besides, how do you kill Death? War, alright, with some hassle you might (although you'd have to face Death for certain, then). But Death itself?

Murphy thinks it's not possible.

Connor thinks otherwise (he's an adherent of the 'one soul' theory), but keeps his opinion to himself. They get into fights enough as it is, which is no real surprise — aside from being brothers, and twin ones at that, one of them is War, after all. That kind of implies an ill temper by default.

And an ill temper Murphy has — banter being the most innocuous of its manifestation. Bar fights come second, with endless goading and more than a little liquid courage. Although Murphy doesn't need any, he likes to indulge in human sins ("Drinking, a sin? Brotha', yer off yer rocker! Check the list again!" he'd say), under the pretense of keeping appearances. They can't exactly wander around with their black, menacing wings outstretched to full span. Even if they did, they probably wouldn't fit in any room, anyway.

"Why the smug look, Murph?" Connor glances up at his ruffled brother just as the latter corners him, bending at the waist and planting his hands firmly on the ratty mattress Connor's sitting atop.

They don't really need to sleep, neither do they posses the need for an apartment, or a job, for that matter.

But they still do have those things. They cling to them, anchoring their existence to the life they've left behind. Nothing much is different, the clock is ticking on the tenth year of their rebirth, and there are still strings attached to their backs, pulling them to the people around them.

They don't yet bear the wisdom of an old soul, but they've endured enough suffering for their lifetime.

They don't know about the other Horsemen. As far as they're concerned, they haven't yet appeared in this world, and the brothers have to wait for their arrival. It could take days, years or centuries — they do not know.

But they've been promised comrades, brothers, and thus they shall wait.

Murphy's not too keen about having two other 'brothers', and Connor doesn't like it much either, for he will always have only one. But the promise of camaraderie seems pleasant enough.

Maybe, if the other two are, indeed, old souls, they will be the guiding beacons to the MacManus twins.

Connor thinks it funny that Death needs guidance, and although he has voiced his mockery more than once, deep down he acknowledges the need.

"Why, I aren't allowed ta look at me brotha'?" Murphy smirks right in his face, noses inches apart, and Connor grins in return.

Sometimes he still doesn't believe they're not humans anymore. Not two Irish lads. But the gentle flow of electricity flowing through his body reminds him of the enormous energy contained inside, of two humongous, sharp wings behind his back.

It took them half a year to learn how to control those things. They had to 'leave to Ireland to visit their Ma' to stop any and all suspicions upon their sudden disappearance, when in reality they had spent six months holed up in a warehouse in the outskirts of Boston.

Even there they had trouble moving around, constantly toppling over each other's wings. By the second week they started experiencing cramps in their shoulders and joints, due to the lack of proper stretching and movement. For being ephemeral, those large fuckers sure ached like the real deal.

Although to be fair, they had learned later on that any part of their otherworldly appearance, when manifested into the human realm, became a real part of their body, with ensuing consequences.

"Look all ye want, eejit," huffs Connor, slipping his eyes to half-mast as Murphy moves in closer, brushing the cold tip of his nose against his twin's cheekbone.

One thing Connor's happy about is that their 'jobs' don't differ much from what they did before. Except now they have to come after the innocent ones, as well as the bastards.

That still grates on Connor, but he gets the necessity of the act. Murphy, though, Murphy has it harder than he.

When Connor is alone (and those moments are rare), he can't help but think of his brother, for he seems to have gotten the short straw.

Sure, he still spills blood together with Connor, but now... Now he riles people up like never before, seeming to drink in the yells and the punches, the shattering glass and the broken bones, the lives taken away by pure, unadulterated hatred. He thrives on this madness, his body vibrating with glee as all hell breaks loose around him.

Later, at night, Murphy breaks down and cries, covering his face with shaking hands and asking Connor why. Why, why, why? He is the justice, he is the divine punisher, he isn't some monster fed by the chaos, whose mere purpose is to spill blood, any blood.

Those are the nights Connor holds him the tightest, shushing his twin and telling him the truth (for that is what he stands for). He tells Murphy that he is not the darkness oozing from his pores, that he is not the chaos of the soul, but merely the noise of his emotions, and if people are too foolish to drown in the wave of hatred, then let them. No innocent, good person will harbour such feelings merely because of Murphy's presence, and if they will, the corruption must have taken hold of them long before Murphy.

Murphy doesn't seem to believe him and continues blaming himself, and Connor's heart breaks and shatters over and over again, because there is nothing he can do.

He can't say that his twin got the role conflicting with his self. Murphy was always known for his temper tantrums, his instability and a knack for violence.

But the essence of War, when dug further, goes against the grain of Murphy's morals, and that's what pains him so.

Right now, though, Murphy is smiling, chapped lips brushing against Connor's stubbled cheek.

"Want ta go out tonight?"

"Aye, sure do, brotha'," Connor falls back on his hands, leaning away from Murphy.

His twin follows, crawling up the bed and boxing Connor in, a wide, feral grin adorning his handsome face.

"Wanna stretch yer wings fer a bit, Conn?"

The elder MacManus leers, "Aye, with pleasure."

They don't have to manifest them to run the streams of energy up their non-existent veins, pushing out the kinks and kicking up the circulation, or an analogue of sorts.

A bright, strong impulse of pleasure is sometimes more than enough.