My Girlfriend is the Nether King

Eighteen years ago, a mysterious infant pushed open the Spirit King's door that was sealing away three Primordial Demons of the spirit realm and released the Nether King who was imprisoned within;
The fourth generation Spirit King sacrificed his Yin Soul to reseal the Spirit King's door, and as a result, the spirit realm underwent a change of rulers, causing widespread chaos…
Eighteen years later, an eighteen-year-old high school student was involved in a car accident, and his cloudy left eye, which had been unclear since childhood, suddenly began to see spirits.
With true hearts joined, the young man and his girlfriend made an eternal promise to each other.