I'm thinking it came from a hero (or a really powerful villain) that knows about Mc's power's and how he is the only villain that can have more than 2 powers. So to deal with MC more efficiently they have to get rid of his (the original body owners) sister. Basically I think they're trying to either kill her or actually just send her away to recruit or kill MC.
I think it's pretty sus a random manager in another country getting a call for them to come to America I bet they have plenty of other people in their chain of restaurants just as good or better at they're jobs I kinda feel like the mc is gonna push her to go and she'll get killed off but that's just my opinion

I wanted to ask the readers that read Chapter 27, What do you all think about Kang-Woo’s sister receiving the invitation for America like that?What possible theories about the mysterious person on the phone and what they could be plotting. Wanted to hear(read) everyone’s idea