
"Something happened that night that made them both gain "powers"
While YeonWoo managed to master that power, which has some relation with mirrors and the house itself too, Teasing is still struggling but he'll probably eventually be able to master it too. And when he does, he'll also become kinda evil like yeon woo.
There is definitely a relationship between the house and yeon woo, when yeon woo gets mad, so does the house. If you know the movie Monster House by Pixar, it gives that vibe.
Another theory I have is that they sold their souls to kill the parent and have demonic powers with them now that would explain why people get killed idk tho."
This was my theory i posted in January lmaoo and it turned out more or less true
*starts ugly crying at the double rings*
I'm so happy for them