Karen Nagase (永瀬 かれん), born on October 13, 1996 in Chiba Prefecture, is a Japanese AV actress and strip performer currently affiliated with Bambi Promotion. She began her career in April 2019 under the name Mai Motoyama (本山 まい), represented by Forty Four Management and debuting with Prestige. She later adopted the name Nanase Karen while (七瀬 かれん) affiliated with BELLTECH, before transitioning to her current name and agency in December 2023. She made her striptease debut in July 2023 at Shinjuku New Art and has since performed at venues like Asakusa Rockza and Roppongi's Red Dragon.

Standing at 155 cm with measurements of B86/W57/H88 cm, Karen describes herself as having a soothing, laid-back personality. She enjoys watching foreign dramas, practicing beauty care, dieting, and relaxing in hot stone spas. Despite her calm demeanor, she has an energetic side shaped by childhood experiences in horseback riding and dance. Her favorite things include K-pop idols, Japanese cuisine, and the color light blue.

Her hobbies include watching Netflix and foreign dramas, beauty care, dieting, and hot stone spa visits. Though she describes herself as laid-back, she has an active side rooted in childhood experiences with horseback riding and dance. She maintains a close connection with fans through social media, where she shares updates and coordinates appearances.