This is the most adorable reason to dress as a gal and show up at your co-worker's place when they're sick acting like a totally insane thrill-seeker who just finds random people saying they're lonely then goes into their homes.
Like only half-joking, too. She's an incredibly cute character. The setup here is fascinating because of how deeply creepy it is, but how endearingly cute and lovable SHE is. It's the first time I've ever really bought a yandere thing. It's also very focused on her point of view. Partially because her actions require the most explanation, but the fact that we're getting them makes this whole thing feel so much different. Just think about how different this all would be if we didn't know who she was: we'd be stressing about the two female leads and there'd probably be all sorts of people calling her alter-ego a filthy slut whore who should just die.
She is very much the main character of this, even though the first two chapters were from his perspective. Which makes me both hopeful and afraid; I really want her love to come true but the fact that we're given so much REASON to root for her but the male lead is largely in the dark makes me anticipate that he will not be okay with any of this, even though we now know he's the reason she's doing it. His advice that sometimes you should just act a little different to get along with others is something she took to heart, so she invented this whole persona to be there for him when she thought her regular self shouldn't be.