In the book "The Blood of Olympus" by Rick Riordan, a character named Nico expresses joy with a grin, something he isn't familiar with doing. This smile indicates a moment of relief and happiness, showcasing a change in his emotional state.
He inquires about Mellie and the baby, highlighting his concern for their well-being. This moment reflects his personal growth and connection with others, indicating that despite his usual somber demeanor, he is capable of warmth and caring for those close to him.