ZUBERfox

Sora and Shiro are a pair of siblings, brother and sister, who are well known as brilliant. Yet they are NEETs - useless to society, and (Not in Education, Employment, or Training) - and even worse they are completely house-locked shut-ins (hikikomori!

Yukiteru "Yuki" Amano is a loner who spends most of his time writing a diary on his cell phone or talking with his imaginary friends Deus Ex Machina, the God of Time and Space; and Murmur, Deus' servant. One day, Deus gives Yuki a special diary, mentioning something about a game.

(Wiki) Keima Katsuragi, a second-year high school student, is an avid bish?jo game player.