1. The defendant (Counterclaim plaintiff)'s appeal is dismissed.

2. The defendant-Counterclaim plaintiff's counterclaim filed at the trial.

1. The reasoning of the court’s explanation of the judgment on the principal claim is the same as that of the judgment of the court of first instance, and thus, the judgment of the court of first instance is accepted by the main sentence of Article 420 of the Civil Procedure Act.

2. Determination on a counterclaim

A. The summary of the defendant's assertion is that the defendant applied for a compulsory auction on each real estate owned by the plaintiff B and the deceased with the judgment of indemnity of this case as executive title, and paid a sum of KRW 633,036 in the auction procedure. Since this is based on the causes attributable to the plaintiffs, the plaintiffs are jointly liable to pay the above KRW 633,036 to the defendant.

B. On the other hand, the costs alleged by the Defendant constitute the execution cost as above. The expenses for the execution not reimbursed in the compulsory execution procedure should be separately applied for a decision to determine the execution cost and executed with the execution title (Article 53(1) of the Civil Execution Act, and Article 24(1) of the Civil Execution Rule), and a separate lawsuit seeking payment of the amount equivalent to the execution cost to an obligor as a separate lawsuit is unlawful as there is no benefit of lawsuit (see, e.g., Supreme Court Decision 2015Da2393, Sept. 10, 2015). Therefore, the Defendant’s counterclaim is unlawful as there is no benefit of lawsuit.

3. In conclusion, the plaintiff's main claim is justified, and the judgment of the court of first instance is just, and the defendant's appeal is dismissed. The defendant's counterclaim filed in the court of first instance is dismissed, and it is so decided as per Disposition.