You didn't like it.
You never liked to do those things.
You didn't have to do them, either.
They were just commissions: money in exchange for blood; the blood of others, the blood of innocents.
Do you remember your first time?
She was fairly young, for the average of her town. And someone wanted her dead.
You lured her into an isolated alley, and grabbed her by her mane. You pressed a hoof on her mouth to shut her screams, and unsheathed your knife, levitating it in front of you with your horn. You were shaking uncontrollably, and she knew it: she started crying, begging for mercy under your grip on her mouth.
But you had gone too far, at that point; you couldn't stop what you had started.
You aimed the point of your knife to her throat, shortening the distance little by little. She was kicking the air, trying to escape your grip on her, but you didn't stop.
As your knife started poking the skin of her neck, she suddenly petrified, too scared to make a single move, but too traumatized to stop crying, sobbing and whining.
Your blade started to cut into her skin, penetrating slowly but steadily, deeper and deeper into her throat; her hoofs went to grab the handle of your knife, desperately, but too weakly to counter your magic field around it.
Blood started to drip from the lips of the cut, as the blade reached the inside of her throat: she was coughing blood on your hoof, without stopping to cry in fear.
She drowned in her own blood, before she could die by bleeding out, her moves getting weaker and weaker as less and less oxigen could reach her brain. slowly, she died in your own hoofs, her mind slowly descending into oblivion, as she breathed in one last gulp of blood; you let her go, and her corpse dropped dead to the dust of the road, a small pond of blood spilling under her head.
You teleported away, stains of blood on the coat around your hoofs, and all over your knife. Once safe, in the darkness of your home, you let your bloody knife fall to the ground, and dropped on your knees, crying like a foal. You were rubbing your bloody hoofs all over your face in desperation, leaving trails of that mare's blood all over your coat. Only then, you realized that you had started something horrible, something that you could never have the strenght to stop.
And of course you didn't stop there; you needed money to move from that city, and you needed it fast.
You did it once again: that time, you snuck up on him while he was working to repair a window of his cottage, and hit him in the back of his head with a hammer. He fell to the ground unconscious, and you hit him again, and again, and again, until his brains were just an undistinguished bloody mass, splattered everywhere on the floor.
You were looking him in the eyes while your weapon went down on him, his desperate eyes begging for a mercy that would never come. You were shaking under his look, but yo didn't stop, until nothing remained but a corpse with a smashed head.
You ran away.
You kept running away for a couple of years, murdering and then escaping from the Royal Guard and from your own thoughts; you had to run and to kill again, or else you would get crazy over the horrible things you did.
How many of them did you kill? How did you kill those poor souls? how many of them were mares, fillies, and foals?
You didn't care. But it wasn't really your fault.
You just had to kill somepony to get more money to move again: how does it matter who you murder? Trying to think about that would mean to stop, and then think about all the others.
You didn't like to do that, but you became addicted to it somehow. It made you travel all around Equestria, but you didn't really see any of it: it was all dark, and all you could see was your next target, the money, and the blood on your hoofs that you just couldn't manage to get washed off, no matter how far you ran, or how fast.
