Born in 2004, Yamaguchi Kira is a rising actress, singer, and dancer under LDH. She was born in Nagasaki and attended EXPG Fukuoka. While she was in EXPG LAB, she was a member of the dance group KIZZY. Whilst participating in LDH's "The Girls Audition" in 2018 under the Actress Category, Takashi Miike confirmed that a successful applicant would receive a role in one of his works. She later won and became one of the main roles in Miike's "Secret x Warrior Phantomirage" in which she also became a member of the idol unit they released through the series called mirage². Currently, she's a member of LDH's girl group, Girls². She is also in one of Girls² units called, Oha Girl from Girls² in which is a unit for the children's morning show aired by TV TOKYO called, "Oha Suta". She is assigned as Tuesday Oha Girl along with fellow member, Masuda Kurea.