Why is Little Talks by Monsters and Men the most accurate song for Endo and Celestia- (aka, two of my fox OCS who were dating in the middle of a war...)

Celestia and Endo were best friends almost immediately when Ocean brought Endo to SG. They started dating after some nights of watching the stars...Cel was the first to accept Endo for all of his nervousness and silliness...They did care about each other a lot and were dating, both of them 19, when Cel was killed in battle at Starsguild's original base...ever since, Endo has had her voice in his head...and he wants revenge for what happened...he's covered up the hurt from what happened with jokes, but he still talks to her in his head, ever so often...