Perseus Jackson, Chinese God Of Ice

Percy Jackson was betrayed by Annabeth during the war with Gaea, later everyone thought that he suicided, except for Annabeth.
What was left of the seven, including Nico and some others were offer immortality.
Fifteen years later, Percy and Camp Half-Blood once again meet, except Percy changed, so much that they barely recognized him, watch how the plot develops.

(Fan fiction of Percy Jackson, cover isn't mine but that's how Percy looks in my version.)