Solo Leveling, Vol. 3 (light novel)

When Jinwoo gets his rank reevaluated, the results are even better than he could have dreamed of... but more importantly, a chance to heal his mother from her strange illness falls into his lap. In order to find the cure, he must make his way further into the Demon's Castle - and now that there's finally hope at the end of the tunnel, nothing can get in his way.