Solo Leveling, Vol. 15 (Comic): Side Stories 2 -

Much to Jinwoo and Haein's surprise, their toddler son is showing signs of inheriting the powers of a Shadow Monarch! Luckily, they're able to suppress his abilities to give him a normal childhood...but years later, something strange starts to happen as the now teenage Sooho suddenly starts to have strange dreams about being trapped in some sort of dungeon with monsters galore!