The tale of twin blades.
There is only once force greater then that of God, the devil, heaven or hell. That is the cosmos. The cosmos is the center of all universes, where it will begin and where it will end. The cosmos is the true Alpha and Omega. But mankind has long since forgotten about this and has created new figures and idols to look up to.
Before the hands of time had begun to tick, the beings that were the cosmos created both good evil. Both of these values grew from the tree but separate at the branches. Darkness and light are one in the same yet different. It depends on how one looks at it.
Along with such powers given, there must be a way to put an end to it, should the time come. Two swords were forged. Both made to destroy the other. Should these swords fall into the hands of the greedy or unworthy, chaos will unleash itself? The end to all worlds would commence, and no one would be safe from this destruction.
Which is why the cosmos ruled it that only the ones 'pure of heart' would be able to handle these swords?
But it has been argued, 'who is truly pure of heart?'. The answer is simple. The swords were made to take ones insecruties,uncertainites, fears and sadness and use it against them. It will drive its holder to madness, thus destroying them. A destroyed mind can only bring destruction. But he can see past his faults, his fears and insecurities, is the one truly pure of heart. He who can see the swords true potential and not let it break him in the end. This person must understand that sometimes, death is not needed to bring forth peace within thyself.
Each sword resides in its resting place, never to be touched, and it never should be. But if the times arises, the blades will awaken, and they will either go against one another or fight together. The choice is within the holder.
The choice remains. The swords sleep. Until the time comes.
And that time is near.
That's the basic outline of origins of the swords. Who made them and what they can do. If anyone doesn't understand, I will explain it all.
The cosmos is the highest power. Hell isn't greater and neither is heaven. The cosmos was the first thing here before earth. In this story, the cosmos made earth, Jesus, Satan, any figureheads. So it answers the question, if the sword falls into the hands of the wrong hands (i.e., demons and angels, I'll get into that in a moment) the world will come to an end. Not just the human world, every word. Hell and heaven included in this, because the cosmos saw it as, if a person could be greedy and wanted to rule all by killing the other, he or she will die a thousands deaths and so will his/her comrades, enemies and innocents. That's how it was ruled. It can't be changed and there are no exceptions.
Now, why can't an angel or demon use the sword properly when it was made to destroy one another? Its simple. The sword uses everything against the person, and since they are holy/evil/dark/light they won't be able to handle it. If Omreiz were to use the sword that killed all demons he would be driven to madness. He's too powerful (since he's an angel) to handle it. He's not in the limbo between heaven and hell. It would be the same way if Belial got his hands on the angel one. He's too powerful and the sword will go against him, driving him insane as well.
So, who gets to use the sword?
Humans, halflings, or in rare cases and half demon/half angel.
Why? Because human's can be used either way. Technically no human is either good or evil. They aren't from heaven, they aren't from hell. That is decided when they die. Not when they live. The sword still does, however, use everything against them. But in this case, a human could handle it, since he doesn't have any powers, and he doesn't come from a certain world. He is the limbo. If he listens to the voices that the sword sends him, he will destroy the worlds. If he choses to see past his faults and fears, he will know the swords true potential, which is destroy it.
And as for halflings or both? A half angel or half demon could withstand it better then a full one could. The affects are still the same but since they're only half the choice is theirs to make. It applies for the humans. Now, for the special cases where the person in question is half demon AND half angel. This is very tricky. Its walking on a thin sheet of ice. It could fall or could withstand it. We'll use Brahma as the example since he is the only one. If Brahma were to take the sword to kill all angels he could use it. But if he leaned a certain way, whether it be the demon or angel in him, it will break him. It all depends on how much he could withstand and if he'll give into the voices the sword sends him. Its the same way with a human or a halfling. The sword can make or break you. If any demon or angel tried to use it, the sword would eat them alive.