Zero was a victim of the War of Harem. Two years of his journey as a demon in a world resembling a game he once played ended in a tragic death. Fortunately, his soul returned to Earth. On Earth, he was no longer Zero, the Shadow Villain, but Ernest, a runaway child haunted by an inferiority complex. Until ... "So, you wanted us to get married so that you could make me your furnace?" He ended up being a furnace for his new wife.   Behind his role as a furnace husband, he gathered strength and became a shadow once again, ruling the world from behind with the help of the system and skills from the previous world. *** Slow-paced story. Please leave a positive review if you enjoyed reading this. If you have criticism or suggestions, please just say so. Thank You.