@Giyu gf mi eum's dad was paid to kill youngjitae by a powerful individual. Mi eum saved him and got injured in the process, which is why his memory is fûcked and there's a big scar on the back of his neck. That's p much it, although the chapter before this one gets into who it was that paid mi eum's dad to kill young jitae.
@Giyu gf they were close when they were young. mi-eum's father used mi-eum to get close to hajoon because he wanted to kill hajoon. mi-eum's dad was ordered to kill hajoon by jian's mother due to internal feud in the company. so, this happened and probably back then there was water trickling down the tap where hajoon was confined after being kidnapped and that is why he doesn't like the sound of water dripping. mi-eum, as trauma response, forgot about hajoon and that memory. now they've met again. jian specifically sent mi-eum to hajoon because he knows that hajoon will open up to mi-eum
@Giyu gf the mom's the one who paid mi-eum's dad to kill jitae. Pretty sure it's his step mom. And his half brother who works with the mom. It's a typical "fighting for inheretance of a super successful chaebo" feud
