Incarnate Rain

The planet of Marue has dark cloud covering is inhabitants. A hundred years ago, its civilization reach its peak. In the dark hour clouds begins to cover their city. The rains begins to fall like any other day, but this spawns demonic creatures that almost destroyed their civilization. The world enter is post-apocalyptic era. The remaining major cities build their defense Corp's to fight these beings. Each city has their teenagers trained for incoming attacks if these beings. Since little is known about this beings, three special teens Esko, Dregg, and Creed may shed some light on this mystery