Jasico is a slash ship between Nico di Angelo and Jason Grace, from The Heroes of Olympus fandom. 


In The House of Hades, Jason is the first to learn about Nico's crush on Percy and they are good friends. During the events of The Blood Of Olympus, where Nico had volunteered to return the Athena Parthenon back to the Greeks, Jason prayed and sacrificed a bit of his mess everyday to hope that Nico makes it out alive.


The ship is not canon but many Jasico shippers state in fan fiction that Jason got him over Percy.