B. In a case where a creditor subrogation lawsuit is pending, whether the same creditor's other creditor files a lawsuit based on the subrogation right against the same subject matter of lawsuit (affirmative)

(c) Criteria for identifying the previous and subsequent lawsuits in the case of the preceding paragraph;

D. Whether the purpose of Article 405(2) of the Civil Act is to prohibit the management and preservation of this right (negative)

E. Whether the intervenor's claim and the plaintiff's claim are compatible, but the independent party's participation under the latter part of Article 72 (1) of the Civil Procedure Act can be made (the participation in prevention of harm) (affirmative)

F. Whether there is a benefit to seek confirmation of invalidity of a juristic act which is the cause of a claim against another person in a case where his/her own right or legal status is likely to be infringed as a result of a fraudulent act which is the cause of the claim between others (affirmative)

B. If a creditor subrogation lawsuit is already pending in the court, if another creditor of the same debtor files a lawsuit based on the creditor's subrogation right against the same subject-matter of lawsuit, the lawsuit which has been pending later is an improper lawsuit which violates the principle of prohibition of double lawsuit.

C. In the case of the preceding paragraph, the criteria for determining the judgment of the previous suit and the subsequent suit shall be followed after the time when the complaint was served on the defendant, i.e., the time when the lawsuit was pending, and it shall not be determined on the basis of whether the previous suit and the subsequent suit are filed, even if the procedure for preserving provisional attachment

D. If a creditor starts to exercise the debtor's right on the ground of subrogation, permitting a disposition such as transfer or renunciation of the right which is the object of subrogation to the debtor would impede the exercise of the creditor's right of subrogation. Thus, it is the purport of Article 405 (2) of the Civil Act to prohibit it. Thus, since the management and preservation of the right that does not interfere with the exercise of the subrogation right is not prohibited, the creditor Gap's exercise of the right of subrogation against the third debtor Byung in subrogation of the debtor Eul cannot be a disposal act in place of management and preservation of the right, and therefore, the exercise of the right of subrogation against the debtor Eul's exercise of the right of subrogation cannot be viewed as a disposal act in place of management and preservation of the right. Therefore, the exercise of

E. The latter part of Article 72(1) of the Civil Procedure Act, in the case of participation in the prevention of death is likely to infringe upon the rights or legal status of a third party as a result of the action for death, and the third party is allowed to participate in the action to prevent such infringement in order to prevent a judgment rendered as a result of the action for death, so it objectively recognized that the plaintiff and the defendant have the intent to harm the third party through the lawsuit, and in case where it is deemed that the third party's rights or legal status is likely to be infringed as a result of the action, even if the claim of the third party and the plaintiff's claim are in a relationship consistent with logical reasoning, the independent party intervention as stipulated in the latter part of Article 72(1) of the Civil Procedure Act can be conducted.

F. In a case where the legal status of one’s own rights or legal status is likely to be infringed as a result of a fraudulent legal act committed between others as the cause of a claim, there is a benefit to seek confirmation of nullity of the juristic act which has caused the claim against others. This is because it is an effective and appropriate means to prevent infringement of one’s rights or legal status by being declared and executed as at the end of the above claim for confirmation of nullity.

The defendant assistant Seoul Metropolitan Government's appeal is dismissed.

The costs of appeal dismissed shall be assessed against the above assistant intervenor.

(1) Since a lawsuit does not constitute a double lawsuit as a requirement for a passive lawsuit, it is a matter of ex officio examination by the court. Thus, even if a party's assertion regarding it is not significant to urge ex officio action, it cannot be a defect which can be considered as the ground for appeal for the omission of judgment, even though it was not judged. If another creditor of the same debtor's claim is already pending in the court when a lawsuit based on a creditor's subrogation right is brought against the same subject matter of lawsuit, the lawsuit which remains later in time shall be an illegal lawsuit brought against the principle of prohibition of double lawsuit (see Supreme Court Decision 87Meu1618 delivered on September 27, 198). In such a case, the criteria for determining the previous lawsuit and the subsequent lawsuit shall be based on the prior date when the complaint was delivered to the defendant, i.e., the time when the lawsuit is pending, and even if the procedure for preserving provisional seizure and provisional disposition was completed prior to the filing of a lawsuit, it shall not be determined based on this (see Supreme Court Decision 87Meu3155, Apr. 111, 1989

According to the records, in order to preserve the right to claim for ownership transfer registration against the defendant Seoul Special Metropolitan City by the assistant intervenor of the defendant Gangnam-gu and the right to claim the provisional disposition of real estate on January 24, 1986, the plaintiff filed a lawsuit on February 26, 1986 on the ground that the plaintiff's lawsuit of this case was filed on February 5, 1986, and therefore, the plaintiff's lawsuit of this case constitutes double lawsuit cannot be accepted.

(2) At the time the obligee started to exercise the obligor’s right on the part of subrogation, permitting a disposal act, such as transfer or renunciation of the obligee’s right, which is the object of subrogation, would hinder the obligee’s exercise of the obligee’s right on the part of the obligor, and thus, prohibiting it is the purport of Article 405(2) of the Civil Act. Thus, the management and preservation of the right that does not interfere with the exercise of the subrogation’s right is not prohibited. The Plaintiff’s claim for ownership transfer registration against the Defendant, Gangwon-gu Seoul Special Metropolitan City, which is the exercise of the Plaintiff’s exercise of the right on the part of the Plaintiff, cannot be said to be a management and preservation of the right, and it cannot be said that the exercise of the claim for ownership transfer registration by the order for prohibition of disposal as seen earlier, which was obtained by the obligee

2. As to the grounds of appeal by an independent party intervenor:

(1) On December 30, 1985, the participatory lawsuit of this case is sought by the plaintiff for the execution of the procedure for the registration of ownership transfer on the ground of a contract for payment in kind for the real estate of this case against the defendant Gangseo-hee. According to the plaintiff's reasons for the application for participation by the independent party intervenor, the plaintiff agreed on November 9, 1982 that the above real estate was sold as a security at the time when its future ownership is expected to be transferred to the defendant, and completed the registration of ownership transfer or the registration of ownership creation of the neighboring real estate No. 1 until August 17, 1983, 40 million won was leased on four occasions between December 22, 198 and December 28, 1985, and the above land substitution became final and conclusive as the substitute land of this case and caused the defendant to take the procedure for the above real estate, and the defendant had the right to transfer the above real estate again to the plaintiff's third party's obligee's claim for payment in kind and 585.

As to this, the court below decided that a third party's participation in the lawsuit is his own right or whose rights are infringed by the result of the lawsuit and participates in the lawsuit as a party and resolve in a lump sum without contradiction between the third party's conflicting rights or legal relations. Thus, an independent party intervenor must make a separate claim that is incompatible with the principal claim against the plaintiff and the defendant in the lawsuit seeking priority, and even if a separate claim is made in the form of records, if the claim is unlawful because there is no benefit in the lawsuit, the independent party's participation is unlawful, the court below held that the independent party's request for revocation is unlawful, and based on the premise that the independent party's request for revocation is unlawful. The first claim for revocation against the defendant Kang-hee who is an independent party's debtor, who is not the defendant's standing. Thus, it is hard to confirm that the plaintiff's claim is unlawful. Second, the plaintiff's conjunctive party's claim for registration of transfer of ownership and the plaintiff's conjunctive party's claim for return against the defendant's conjunctive party's principal claim for the payment of this case cannot be seen as unlawful.

(2) Article 72(1) of the Civil Procedure Act provides that a third party who claims that all or part of the subject matter of a lawsuit is his/her own right or claims that the rights shall be infringed upon by the outcome of a lawsuit may participate in the lawsuit as a party. If the plaintiff and the intervenor asserts that they are their own rights, such as the case of participation in the proposal of rights under the former part, they may belong only to either the plaintiff or the intervenor regardless of the plaintiff. Thus, the plaintiff's claim against the defendant and the intervenor's claim against the defendant may not be compatible with each other and belongs to anyone of their rights, but it does not necessarily need to meet the strict requirements in the latter part. Unlike the case of participation in the proposal of rights, where the third party's right or legal status may be infringed upon as a result of the lawsuit, the third party may participate in the lawsuit in order to prevent the judgment that becomes final and conclusive as a result of the lawsuit, so even if the third party's claim and the intervenor's claim against the plaintiff and the intervenor's claim against the third party are objectively consistent with the above third party's opinion and the third party's claim.

The reasoning of the judgment of the court below in this case is as follows: first of all, the plaintiff's claim for the revocation of the fraudulent act against the plaintiff by the independent party intervenor is justified is based on the time of the court below's determination; and even if the claim for the revocation of the fraudulent act against the plaintiff by the plaintiff by the defendant by the defendant by the defendant is unlawful, if the other claimant's claim for the revocation of the fraudulent act against the plaintiff by the defendant by the defendant by the plaintiff by the plaintiff is legitimate, the plaintiff by the plaintiff and the defendant is legitimate, the plaintiff by the plaintiff and the defendant. In addition, the court below's conjunctive claim has no legal interest in seeking the nullification of the payment contract between the plaintiff and the defendant by the plaintiff by the plaintiff by the plaintiff and the defendant by the plaintiff, but if there is no possibility that his right or legal status may be infringed as a result of the fraudulent act as the cause of the claim between the others, it cannot be denied the interest to seek the confirmation of nullity of the juristic act which caused the plaintiff by the plaintiff by the plaintiff by the plaintiff's claim for revocation of the invalidity.

In addition, even if it is based on the evidentiary materials submitted by an independent party intervenor and the whole purport of the argument and materials and arguments submitted by the plaintiff to prove the fact of payment in kind, the litigation between the plaintiff and the defendant Kang Jong-hee takes a scam enough trace of fraud. It is reasonable that the court below erred in the misapprehension of legal principles as to the requirements of participation by the independent party for the prevention of corruption and thereby adversely affected the conclusion of the judgment by misapprehending the legal principles on the requirements of participation by the independent party for the prevention of corruption, without examining and determining whether the plaintiff and the defendant Kang Jong-hee have objectively recognized the intent to harm the intervenor through the execution of the participation lawsuit in this case and whether there is concern that the intervenor's rights and legal status may be infringed. The arguments are reasonable.

Therefore, the judgment of the court below is reversed, and the case is remanded to the court below. The appeal by the defendant assistant intervenor in Seoul Special Metropolitan City is without merit, and the costs of appeal are assessed against the losing party. It is so decided as per Disposition

Justices Yoon Young-young (Presiding Justice)