
I can't remember why is he that sick?

In ch.32, they said the 2nd prince (that bastard that was banished to the north in the end of ss1) poisoned him, maybe for years.
https://iweb13.mangapicgallery.com/r/newpiclink/the_lady_s_law_of_survival/32/a49f204ec2ecae081463b2d2ae196c36.jpeg
King better shouting Saitama's name and come like an ultimate skill or something xD