A/N: Inspired by the prompt "For what would your character give their life?"; set a few months after "In All Things Light and Dark".
Reparations
It takes several months for Malthael to accept that he can leave Tristram. The town is not a prison. Neither is Tyrael's home, though it is a retreat for him where he may sleep with a roof over his head. The chains he feels are not crafted by the Nephalem. They are, instead, the product of his own distrust of himself, and what he might do, directionless.
In Salvos, he had purpose. He protected. He learned about himself. Here, in Tristram, he sees his life's destination blurred. Tyrael is content to train and teach and is a pinnacle of extroverted leadership; Malthael desires something very different.
Change, perhaps. Or more, the dynamism of an evolving world. Where his brother brings order, Malthael craves chaos. Not violence, certainly. Or anarchism. But motion and action, the pulling threads of cause and effect, the fragments of logic that drive the world and that he glimpsed, once, in eternal pools.
And so, Malthael gathers his things, packs his bags, and leaves. He tells Tyrael, because he does not want his brother to worry. Then he vanishes into the darkness. The ground is hard beneath his boots. Fields pass, then forests, and before he knows it, he is deep into the world, alone.
Unlike his first mortal expedition, Malthael is aware of his identity. He keeps it hidden, for his safety and that of others. And he watches everything. The world he travels, the people within it. A part of him knows he is duplicating a journey he made long ago, when he had walked from the Heavens to Sanctuary as an immortal, in search of the sound.
The sound still follows him. But it is tangible now. And it is easier for him to push away the screams and the hatred infusing the world. The emotions he had found overwhelming before are terrible, but they are not the only facets of mortality. Darkness festers, and within it, light still manages to grow.
Malthael travels for months before he realizes what he is looking for. In each city and town, he finds good and evil, light and dark. Where he can, he intercedes on the light's behalf, always working quietly, always tipping the balance to ensure he leaves goodness in his wake. Yet, the human world is fickle, and sometimes his best attempts lead to disastrous consequences.
He requires more information. Or, he is at risk of doing the kind of damage he once did, when he was immortal. Thus, Malthael vows to study the world until he understands it completely; where it came from, and how the Heavens and the Hells shaped it. How they shape it still, for history has become myth in many places. Angels and demons subside in bedtime stories and legends.
In this, finally, Malthael finds his purpose. He collected knowledge once by gazing into the Chalice. The truth is now his to acquire personally. It is not an easy life. The road is harsh, and he sleeps many a night under bridges or in open fields, knowing well that each sleep may lead to ambush and death.
Malthael does not fear death. He understands it intimately, though a mortal drive within him begs him to avoid it as long as possible. He pushes such thoughts away, for now that he has found his duty, his reason for existence, he owes his life, and more, to the world from which he has taken much.
There could be worse things than dying for wisdom. Far worse.