Board Thread:General Discussion/@comment-27997069-20160317174518/@comment-27620479-20160322164412

My theory is that neither Chara, nor Frisk, is the player.

Chara is supposedly the narrator, and although it is easy to miss, they aren't present from the start. Until after meeting Flowey, there is no narration, which can be confirmed by trying to interact with the flowers in the first room (it is only possible after Flowey). Since the player has direct control over Frisk up to that point, that would exclude them as Chara. Also, the player as Chara would mean the ability (and need) of selling their own soul to, (and possibly take control from) themselves.

Frisk isn't the player, because Chara is supposed to be named, and because Flowey can tell them apart from each other after the pacifist run (telling the player to let Frisk go).