The Kept Man of the Princess Knight Novel Volume 3 was written by Toru Shirogane and illustrated by Saki Mashima.

The Dungeon City is thrust into chaos when it is shaken by tremors that hint at an impending monster stampede. Arwin is still inside the dungeon, with no knowledge of the danger she's in, so Matthew insists on going in to save her. Countless obstacles stand in his way: vicious monsters, the sun god's insidious preachers, and of course, the curse he bears that steals his strength when he's not in the sunlight. Prepared to face his death, the weakest kept man ventures into the dark depths of the dungeon.