Defendant D Co., Ltd. (hereinafter “Defendant D”) operated an online site called “private teaching institutes and F,” located in Q Q, Jung-gu, Seoul. Defendant C is the actual operator of Defendant D. From October 2007 to December 2013, Plaintiff A entered into an online contract with Defendant D’s private teaching institutes to provide various services for employment tests at Defendant D’s private teaching institutes from January 201 to May 201. Defendant D Co., Ltd. (hereinafter “E”); Defendant D Co., Ltd. (hereinafter “E”); Defendant D Co., Ltd. (hereinafter “Defendant”)’s 20% of the sales revenue from Defendant E-D’s 2, which was assigned to Defendant E-D’s private teaching institutes, within 0% of the sales revenue from Defendant E-D’s private teaching institutes; and Defendant D Co., Ltd. (hereinafter “E”); and Defendant D Co., Ltd. (hereinafter “E”)’s sales revenue from Defendant E-1, which was assigned to Defendant E-D’s private teaching institutes.