1. The plaintiff's main appeal and the conjunctive defendant are all dismissed.

2. The appeal costs are assessed against the Plaintiff.

1. The reasoning of the judgment of the court of first instance citing this case is as follows, and the reasoning of the judgment of the court of first instance citing this case is the same as that of the judgment of the court of first instance, except for additional determination as to the Plaintiff’s assertion as set forth in the following

2. Additional determination

A. On December 28, 2015, the summary of the Plaintiff’s argument 1) between the Plaintiff and D, the Plaintiff’s argument, as indicated in the instant conciliation protocol, constituted an agreement to reduce the Plaintiff’s obligation to the Plaintiff and to implement the agreement only within the scope of 1.5 billion won, but D thereafter transferred the entire claim pursuant to the instant conciliation protocol to the Defendant, which exceeds the above KRW 1.5 billion. However, on January 5, 2016, the Plaintiff’s representative expressed his/her intent to consent to the assignment of claim to the primary Defendant. This may not only result in additional financial burden to the Plaintiff, but also constitute a false agreement between the Plaintiff and the primary Defendant, and thus, the declaration of consent to the assignment of claim is null and void. As such, the Defendant does not oppose the Plaintiff, who is the primary obligor, and subsequent to the transferee, the Plaintiff is still subject to the exclusion of the Defendant’s claim for the assignment of claim to the Defendant’s primary obligor’s execution title from the execution title’s execution title in the instant conciliation protocol.