The judgment of the court of first instance is reversed and revoked.

Defendant B shall pay to the Plaintiff KRW 70,000,000 as well as to the Plaintiff.

1. The defendant B's grounds of appeal are examined.

The judgment below

According to its reasoning, the court below acknowledged the facts as stated in its reasoning, and determined that there was a reasonable ground to believe that the plaintiff was the right to represent the defendant C at the time of the agreement on the pre-sale of the case.

In light of the relevant legal principles and records, the lower court did not err in its judgment by misapprehending the legal principles on mistake of facts, violation of the rules of evidence, and misapprehension of the legal principles on expression agency.

2. The decision is made ex officio.

A subjective and preliminary co-litigation is a form of litigation in which all co-litigants settle the dispute between each other in the same legal relationship without contradiction, and a judgment is rendered on the claims against all co-litigants (Article 70(2) of the Civil Procedure Act), and it is not allowed to render a judgment only on some co-litigants, or to render an additional judgment on behalf of a remaining co-litigants.

In addition, since the other party's litigation against one of the co-litigants in a subjective and preliminary co-litigants has an effect on all the co-litigants, if an appeal is filed against any of the main co-litigants and any of the preliminary co-litigants, the part of the claim against the other co-litigants is also transferred to the appellate court, which is subject to the appellate court's judgment. In such a case, the subject of the appellate court's judgment should be determined in consideration of the necessity of the conclusion that the main and preliminary co-litigants and

(Supreme Court Decision 2006Du17765 Decided March 27, 2008, and Supreme Court Decision 2017Da207451 Decided July 11, 2017, etc.) B.

The record reveals the following facts.

1. The Plaintiff, even if Defendant B granted the power of representation to Defendant C to conclude the instant pre-sale agreement, is an expression agent under Article 126 of the Civil Act.