@Shelly That girl is the one that appeared in season 1 where a red string was shown connecting Yeon and the girl for a second. My theory is that the girl is Yeon's original soul mate before Yeon tied the red string to Kihoon's finger
Between the lines author PLEASE I BEG YOU FIX THEM PLEASEEEEESDEEREE MY ONCE FAV MANHWA TAKING THE CHERRY BLOSSOM AFTER WINTER PATH STOP ITTTT
Pfp from In the house of the damned/ the mansion summone