what about the hallucinations...... and Yeonwoo telling him to remember quickly since it's confusing or something.Also that black room!!!! WHAT!? Soz
Thats probably from the accident cuz remember they were from an orphanage and usually they r shown as evil plus it also says they disappeared so many traumatic things could've happens at that time
My prediction is they loved each other when they were younger but due to an accident he forgot his memories and was taken away from that place