Mushoku Tensei: Jobless Reincarnation (Light Novel) Vol. 14

CASTLE IN THE SKY

Nanahoshi, Rudeus, and the rest of their group take a trip to Perugius's mysterious floating fortress, seeking adventure and a once-in-a-lifetime chance to learn new magic. What they find instead is disaster as one of their number is struck down by a deadly illness. How far will Rudeus go to save a dear friend's life?