yozora (kingdom hearts)
"If you are who you say, and it was fate that brought us here, then... my path is clear."
The protagonist of Verum Rex, a fictional video game within one of the many worlds of Kingdom Hearts. Apart from his grey hair and heterochromia, his appearance is extremely reminiscent of Noctis Lucis Caelum, a character from the Tetsuya Nomura-directed Final Fantasy XV. Noctis and Yozora's names mean 'night sky' in Latin and Japanese respectively, and contrasts with Sora's own name of '(morning) sky'.
Following his appearance as a secret boss in the ReMind DLC of Kingdom Hearts III, he may not be just fictional after all...