Ah I can hear this term everywhere. Even outside of the otaku society. As far as I am aware, I didn’t hear it last year. Maybe no? Anyway, I realise how much people say this. I assume there is someone who coined it, though…To get to the point, ドヤ顔[doyagao] means an arrogant looking. Like saying, “See? Look what I did, you people.” with a triumphant look. 顔[kao] means looking, but what about ドヤ[doya]?
In fact, ドヤ stems from どうや[douya] which means such an exlamation. Like hey or humph, we have a lot of equivalence. But どうや is actually Kansai dialect[関西弁] so people in Kansai(Osaka or Kyoto) say it. I live in Kanto[関東] so I don’t say どうや, but どうだ[douda]. In this way, や[ya] seems to be used to end the sentence in place of だ[da] in Kansai dialect. For example, I can say コスプレが好きだ[Cosplay ga suki da] or I like cosplay. But if you want to say in Kansai dialect, you can say コスプレが好きや[Cosplay ga suki ya]. Both sound casual, not polite.
So if he is such a doya looking after he did something, he is so sure that his performance is good. He wants you to praise him. I don’t understand why something like this word has been popular, but I guess it could be because such a triumphant looking doesn’t seem to be seen a lot in real life. That is why people with a doya looking are remarkable. So what kind of people are doyagao? Yes, hosts at the nightclubs. Speaking of hosts, I can think of Ouran High-School Host Club. But none of them have a doya-looking in my opinion. At best, it could be Suou Tamaki but not really. He is still the prince, lack of arrogance. What about Yagami Light in Death Note? Oh yes, he is truly doya-looking. Very narcissistic and confident.
In this way, doyagao characters are so popular because once again, few people try to be that way. I wish I could have ドヤ顔, but it’s too difficult because you really have to be smart so that anybody else admires you. Othewise, people would think you are just talk like Oshio Manabu[押尾学]. orz