itsladykit:

Ooh. Good question, Anon. Red was semi-catatonic for the first three years that they were under Muffet’s control. He missed a lot of the more overtly abusive behavior. By the time he was awake, a lot of that went on behind closed doors. He could see how it affected his brother though; he basically fell unconscious, knowing his brother to be sweet and kind and caring, and woke up to a monster that was scarred, mean, and possessing 7LV. (Not to mention unwilling to eat, for some reason.) It was a bit of a shock to say the least. He always suspected Muffet’s cruelty, and he could guess that they were fucking, but he was very much outside looking in. (For a while, Edge was a lot like Razz in that he preferred to push his brother away, rather than accept his help. They got better.)

Edge knows exactly as much as the reader, which is nothing.