Old Gods are invading Earth, possessing humans and baring naked their most wicked emotions. The most powerful 'disciples' of these evil demons are called 'mages'. The story concentrates on two such people: Yoguruma Mugen (disciple of Yogusutoosu) and Narukami Chikage (bound to Nyarlathotep). Their strained relationship and addition of another, seemingly human girl thrusts us into the world where no black or white exist. In this strange and brutal world fight to stay human even in the worst circumstances continues.

The author seems to use lore from the Lovecraftian mythos.

About the title, ダイン (roomaji: dain) is Japanese for dyne, which has the symbol or standard abbreviation of dyn. It is a unit of force that was used in physics starting in the mid-1800s but was largely supplanted by later systems.

See:
http://en.wikipedia.org/wiki/Dyne
http://ja.wikipedia.org/wiki/ダイン