A. (1) The Plaintiff is a construction company that operates real estate development and construction business, and the Defendant Cooperative is a housing redevelopment and maintenance project partnership established to implement a housing redevelopment and rearrangement project (hereinafter “instant project”) in Q Il-dong Incheon Metropolitan City.

(2) Defendant M was a member of the Defendant Union, and R was a member of the Defendant Union on April 27, 2013, and Defendant M was a spouse of R, and Defendant N,O, and P jointly succeeded to R as a child of R.

B. On November 9, 2010, the Plaintiff and the Defendant Mutual Aid Association selected the Plaintiff and S Co., Ltd. as the contractor for the instant project and entered into a contract for the Housing Redevelopment Project (A) with the Plaintiff and S Co., Ltd. (hereinafter “instant construction contract”). At the time, the Defendant executives, including the president, directors, and auditors of the Defendant Mutual Aid Association, signed and sealed the redevelopment project of the Defendant Mutual Aid Association (hereinafter “Co-sureties”) under the construction contract, stating that “The joint and several guarantors, such as the president, director, and auditor, who signed and sealed the following, jointly and severally liable for the redevelopment project of the Defendant Mutual Aid Association.”

Of the instant construction contracts, the contents relating to the instant case are as follows.

Article 4 (Methods of Implementing Projects) (2) Relocation Expenses and business expenses of Gap shall be lent by Eul (referring to the plaintiff and S stock company) to Gap and its members, and Gap and its members shall repay the principal and interest of the lending, such as relocation expenses and the principal and interest of business expenses borrowed from Eul pursuant to the provisions of Articles 38 and 39 (hereinafter referred to as "principal and interest of the loan").

Article 10 (Contract Guarantee, etc.) (1) In order to guarantee the implementation of this project, A shall have executive officers (association head, directors, and auditors) of A as joint and several sureties, and B shall be under the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents.