Fantastic World

Witnessing the death of his parents at a very young age, the main character lives in solitary confinement in a forest while trying to hide from monsters. One day, a creature comes claiming that he's a threat and therefore must be killed. Though bewildered and scared, the main character saves the creature from death. It decides to postpone the killing and leaves without any further revelation of the truth behind the statement.

(Source: Manga Rock)