Somehow, Ace knew what it was the first time he saw it.
It was a blackness. It crawled across people's skin like a sentient ooze, a festering wound or disease.
It was birthed from the shadows that followed their feet and clawed its way to their heads. Curled across their faces until nothing but their eyes was left. Then. Finally when their eyes were swallowed up.. they'd die. By gunshot, by disease, by old age, by drowning. Any way they'd die it'd always be timed exactly by the blackness.
Because that's what it was.
It was death.
Be it death itself, death's presence, their life being drained out of them, or something more innocent such as a timer, it didn't matter. All Ace knew was that the blackness meant death.
And somehow.. he could see it.
Maybe what they said was true.
He was a demon... after all it wasn't normal to see death.
Or maybe since he wasn't supposed to be born, that's why..