Me
I don't read korean but it's not that hard to guess:
You see the girl with black hair and pretty pink lips that dahye was talking to ? (her eyes are hidden) she's going to make a deepfake picture with the ml and the pink hair girl on it, to stir trouble (because it looks intimate, like he got something going on with her). She used an old picture of the ml with an ex-gf. That girl is a stalker, she had/still has a huge crush/obsession on the ml and used to save any picture of him that she found on social media. In fact, she would stalk his social accounts to save his pictures but she would also stalk all his ex-girlfriends by creating fake accounts(?) to also save pictures related to him.
ML had like 3-4 ex-gfs (not sure cuz i dont remember well) therefore she stalks him since a long time.
He told mc that one day...not sure about the circumstances... I think it was a gathering with friends? (he was friendly with her) that girl got drunk so the ML helps and bring her to an hotel and I think she wanted to take a pic or show him something on her phone, however he then found a album photo/folder full of photo related to him lol so he left and he knows she a stalker bitch.
Also the second ml, it seems like he's going to be set with that blond girl, he might fell for her but not sure since I stopped looking at the raws loll
tytyty for this spoiler mwah. YAY justice for our second male lead
who wants spoilers hihi