Akihabara∧Denpatou

Takahashi, a young man who failed his university entrance exam for the second year got kicked from his parents home and had to start living alone in an apartment inside Akihabara's radio tower introduced by his yakuza uncle. There he met a "hero of another world" or to be more accurate, a manga artist girl living on the top floor of the tower claiming to have come from another world. Receiving the mission from his uncle to find the secret of the residents of the tower who, for some reason, all seemed to be almost demented, he was about to start his new life utterly lacking from common sense.

(Source: Novel Updates)