Yu Narukami is the protagonist of the series, and has the attitude of a gentleman, though he maybe quiet throughout the series, we see him having a very odd side, when he's drunk he becomes the opposite of himself, he never shown quite the attraction to anyone but maybe except Yukiko Amagi, but it was never made clear.
Yu Narukami has the ability to have wildcard personas or having multiple personas as his guide, Margaret confirmed that he is the chosen one, his first persona is Izanagi, in the anime series, in a certain episode where Narukami was cross dressing, Chie said that he looked like Izanagi.
The true identy of his parents was never shown, the known relatives of Yu Narukami is his uncle Ryotaro Dojima, and his cousin Nanako Dojima.
Yu Narukami has a gray bowl haircut, and pairing gray eyes. He is 5'11 and he usually is seen wearing the male school uniform. In some point of the series, he is seen wearing various outfits but rarely.