Zorori works at night and starves himself so that Myan, a princess from a video game, will enjoy her time in Zorori's world. Note this is not at the princess's insistence, but instead Zorori hides what he's doing from the princess so that she doesn't worry about him. The princess gets properly upset at Zorori's suffering for her sake.
Zorori and Myan when they meet in the park at the end of that episode is both touching and tearjerking.
Myan: "To me, you'll always be my Sir Hero."
The end of the Monster Major League arc, where the super-strong, super-aggressive, and rather unsocial Gojimatsu realizes what it means to be part of a team when Zorori bats a 300 mph baseball with his tail at the bottom of the 9th with two outs just so the monster could have his chance to bat.