Counterspin said:
Given that the topic is dragonborn, would you be so kind as to tell me which videogame/manga they come from?
Not really a hard question, since things like Dragonborn do appear in videogames and manga. The better question would be why anthropomorphic dragons are
specifically influenced by videogames and manga.
The existence of Dragonlance Draconians (or whatever their name is) is enough to show that such influence is not needed for humanoid dragon-men to appear in D&D. The simple combination of dragons and anthropomorphic creatures (like Minotaurs, Yakfolk, Lizardmen, Sahuagin, etc) is a logical step.
I suppose the idea of making Dragonborn a PC race, rather than just a monster, can be argued to be inspired by videogames and manga... The problem with that is such things are not terribly common even in anime and videogames. I can only name a few examples, myself.
Of course, I don't see the influence of anime and videogames as a problem (though I do see its influence is often overstated on these boards). I would rather have certain races from various videogames I like (Laguz anda Manakete, for example) than boring creatures like Halfings, Gnomes, Half-Orcs, and Half-Elves.