Son of Chaos — T.C. Southwell

A Grey God's shield sphere is his last line of defence, and impregnable, but a domain Key in the hands of a dark god might unravel it and leave him no choice but to flee into the unknown, for to Move within the dangerous and trackless God Realm is to be lost. Bound and powerless, at the mercy of unbelievers with technology, the Demon Lord is doomed unless a light god comes to his aid, but the shackles he wore until Kayos freed him of them have damaged his spirit bond, and he can no longer wield the shadows without healing. Kayos constantly changes the patterns within his shield sphere to prevent the key from working while he waits for his dark son to free him, but his time is running out…