Disclaimer: I don't own squat.
Warning: Conciseness may interfere with intelligibility.
When you come back…
I will be ready. For you will come back, as I have known from the moment I sealed you away. I knew that for all my power, I could only delay the clash that would shake the world's very foundations.
I know you thought it sentimentality, some lingering respect for our old bond that held me back. You thought it the classic weakness, love, mercy, that kept me from destroying you. But you mistook me. I hesitated, at that final moment, staring into your raging eyes, because I suddenly wondered:
Is this right?
I, who am singularly befitted to contemplate my own death, thought, what would it mean for humanity if I was obliterated? I, the shadow at the heart of nearly every human fear, the one inescapable force that limits human potential, a bringer of grief, a quencher of light? Can I justify my own existence? Long ago, in a darker age, when I was something much like you, the question would never have occurred to me. But time stabilized the wildness that accompanied my great power, and age changed my perspectives. Thus, the question was asked, the hesitation inevitable.
But now, at last, I have an answer. Now, I have remembered. Just as madness existed before you, and will continue when you are gone, so too does death exist independently of me. And while time transformed me into a benign ruler, a protector of order, even a source of peace, madness itself is chaos and confusion. Madness traps people within their own minds, so that they cannot love, cannot support one another. There is no respite, no chance to truly live.
And so, my one-time friend, when you come back, I will be ready. For there cannot coexist two Kishin in this world, and if one day Death must be conquered, it will not be by Madness.