Responses

You can see the clauses of the contract in chapter 7... Article 1: the purpose of this contract is to protect "B" from his brother. Art 3: "A" shall proactively protect "B" from "Jeong (Yigon's brother's first name, I would assume). So it's mostly to protect Yigon from his brother and nothing else ig, since the treat that Yigon knew is just his brother. We don't see the rest of the contract so this is just my speculation
In their contract, was it mentioned that ML should protect MC from Brother (only or anything related to his brother) orrr ML should protect MC generally? If its the latter, then technically ML already broke the contract but if its the former, how unfortunate that its only the brother...but oh well.