Bungo and Alchemist -Gears of Judgement-

That man was wandering around. By the suspicious-looking taint, he was trapped in a space of emptiness. If he were to get out and meet him once more, maybe he could figure out who he is. Thus the man meets him again, and realizes what his intention is... That very moment, the whole library is shaken and the impact wraps its surroundings... (Source: Bungou to Alchemist Wiki)