1. All plaintiffs' claims are dismissed.

2. The costs of lawsuit are assessed against the plaintiffs.

1. Basic facts

A. On December 12, 1966, Plaintiff B and C completed the registration of ownership transfer on the land prior to the land substitution, which was conducted on December 1, 1966, for sale and purchase on December 1, 1966. Plaintiff B and C completed the registration of ownership transfer on each portion of the instant land on January 29, 201, on April 10, 1980.

B. Thereafter, on April 20, 2015, Plaintiff B and C completed the registration of ownership transfer on April 13, 2015 with respect to each of the instant 1/2 shares out of the instant land to Plaintiff A.

C. Meanwhile, from May 1, 2005, the Defendant purchased and possessed an unauthorized building and its neighboring marina, etc. installed on the instant land from the previous possessor.

According to the appraisal result on the instant land, the sum of rent from June 1, 2005 to October 31, 2015 was 40,217,340 won, and the monthly rent after June 1, 2015 was 403,740 won, respectively.

【Ground of recognition】 The fact that there has been no dispute, the entries and images of Gap’s 1 through 6, the witness G’s partial testimony, and the purport of whole pleadings

2. Determination:

A. The key point of the party's assertion is that the Defendant occupied the instant land without permission, and thus, the Plaintiff is obligated to pay the monthly rent from the delivery of the instant land and the acquisition of Plaintiff A's ownership to the date of the completion of delivery, and the Plaintiff B and C are obligated to pay the sum of the rent from the Defendant's occupation to the date of the loss of ownership.

In regard to this, the defendant filed a lawsuit against the deceased against the deceased, who was the previous owner, to cancel the ownership transfer registration of the land prior to the land substitution of this case, and thus, the registration of the ownership transfer in the deceased’s name was invalidated. Therefore, the ground for filing a claim against the defendant for unjust enrichment equivalent to the delivery and rent, since the registration of the ownership transfer becomes null and void.