Knights of abyss

This is a story about a man, who wakes up in a ruined city and the fate of this world. Most of the humans have fallen to the corruption of abyss, a darkness that swallows this world. The remaining humans have build a city, a Sanctuary, near a crack in dimension which leads to our world. Thanks to the light from our world that leaks throught the crack, the humans can live in relative safety, at least for now. As the humans were building the Sanctuary, the creatures of abyss were getting stronger and now, they are strong enough to attack the gates of Sanctuary.

Constructive critic appreciated.