In our orphanage, naturally.
Bad people used us for very various things.
At first, we had to do very... nasty things to each other.
Not killing, but rather... taking away one's soul and dignity.
It was not fun, not in the slightest.
But then, they got bored.
They said we are now going to kill each other so we can entertain them.
They learned us how to use weapons.
How to show no remorse.
How to show no mercy.
How to survive.
We could either kill or be killed. There was no point we could go back to.
Unless we would go back to those... previous activities.
We can't really do anything else.
We are, quote, "psychopathic actors and murderers", unquote.
The world pigeonholed us as those. We have no choice but to agree and fight our way through the world.
Leaving as many dead bodies as we can. Right, Dear Sister?(kisses the girl again, but this time the kiss seems... much more suggestive)
Of course, Dear Brother.(giggles sheepishly)

You kids have had it tough.
"All worlds begin in darkness and all so end. The heart is no different."-Ansem