Sumikko no Sora-san

Sumikko no Sora-san (すみっこの空さん, lit. "Petite philosophie") is a manga series by Kanoka Tano. It was serialized in Comic Blade.

Plot
This follows the story of a boy who has returned to his family's home in the country after failing to make his dreams come true. He thinks his way through his predicament with the company of his pet turtle, Platon. More complications arise in the form of a neighborhood kid Sora, who has, for some reason, decided that he is God.