The appeal is dismissed.

The costs of appeal are assessed against the Defendant (Counterclaim Plaintiff).

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. As to the grounds of appeal Nos. 1 and 2

A. In a lawsuit on a property right, it is not permitted in principle to delegate the relevant lawsuit to a third party by delegation of the right holder who has the right to manage and dispose of the rights or legal relations which are the subject matter of the lawsuit.

However, the principle of attorney-at-law representation under Article 87 of the Civil Procedure Act or the prohibition of the trust in a lawsuit under Article 6 of the Trust Act is not a law to avoid the prohibition of the trust in a lawsuit, but it can be allowed in exceptional cases where reasonable grounds to recognize it

(see, e.g., Supreme Court Decisions 83Meu1815, Feb. 14, 1984; 2010Da87474, May 10, 2012). In a case where a management body of an aggregate building comprehensively delegates the management business, including the imposition and collection of management expenses, to an entrusted management company, the authority to claim for a trial on management expenses can be deemed to have been granted.

In such cases, filing a judicial claim concerning management expenses in his/her own name to collect delinquent management expenses in the course of managing the entrusted management company shall be deemed a voluntary litigation trust.

However, it is reasonable and reasonable to allow a management body composed of sectional owners to delegate building management to a specialized controlled entity in order to jointly bear expenses for the management of an aggregate building and to efficiently manage common areas, and such management method is a general transaction reality, and the collection of management expenses is an essential element that is naturally accompanied by the performance of its duties.

In addition, the management of multi-family housing exceeding a certain size, which is a type of condominium building, shall be managed by the housing management operator.