Why should I kill him?
Any other being like myself would. They would break free, spread destruction, bring upon their enemies death as vengeance for imprisonment. They would suffer from a fatal error, however.
They have never been alive.
I have been made to wait in the shadows, again to be patient before taking any action. The difference is that instead of an Amber Seal and nothingness by spell, it has been like taking the form of a shade. I can hear what my prison hears, feel and feed off their fear, anger, sadness. Grow stronger, but to also choose not to act.
Due to this unforeseen occurrence, I have a choice. For once, destruction is not merely my point of being, but rather something I can examine in my state of a 'ghost' to the new life that claims my bones.
And from new experience, new insight, I simply do not see the profit in breaking through to silence the beating heart and reclaim the corpse as it grows cold. To wear rotting flesh when the innocent prison is the perfect guise to get by.
I can extend my will, my power that I grow steadily as time passes on, should I see such a need to. But unless the situation arises, rare it should be in such a life-filled world, why should I draw attention to myself? Why should I suffer defeat again and setback to whatever plan I care to plot while I wait?
Why do I wait? What do I wait for? Simple answers for basic inquiry.
I wait for Death. All things die, and so will the little boy that hides me. I live in his nightmares, and he lives in my body, but one will disappear when the white skeleton comes to collect a soul, and finds only me in its stead. This thing that's given me perspective anew in true patience and understanding will never last. It's a shallow construction that will grow, grow with age, in strength and will. Maybe one day it will try to be rid of me. But that day is long off yet.
And one day this little boy that surrounds me will wear down. Will wear out. With years of life, his life will slowly tick out, and in a final sleep I will rise back up instead.
The Litch is ancient. The Litch is horrible knowledge, is the bringer of destruction, a harbinger of vengeance and of death. Time will release me, flames of green and magic will fuel me, and patience shall bring my enemies their greatest woes.
For while they forget, and they move on, weaken and live, I will remember, I will only grow stronger, and when I next act, there will be none who are capable of standing in my way.