Takamachi, Miyuki

高町美由希

Triangle Heart:
Miyuki is actually the cousin of Kyouya and Nanoha, but she is raised by their family and regards them as siblings. She is very close to Kyouya and is an accomplished swordsman in the Mikami twin kodachi style, just like her brother. She and Kyouya are hired to guard their childhood friend Fiasse, who is now a legendary singer and heiress. Fiasse's actual bodyguard, Ellis, is particularly bothered by this arrangement, and the three guards must learn to deal with and respect one another as they protect Fiasse on her worldwide concert tour from someone who seeks to kidnap her. Miyuki and Kyouya work particularly well together, and she is shown to be very competent on her own, defeating an entire Special Duties Unit team single-handedly in the first OVA. However, Miyuki does not like to fight, viewing it simply as a duty to protect those one cares about.
Mahou Shoujo Lyrical Nanoha:
Miyuki is the real sister of Nanoha and Kyouya here, and lives with her two siblings, her mother Momoko, and her father Shirō. She is a very minor character, but she and Kyouya are still extremely close and remain excellent swordsmen. In one episode, Nanoha, wishing to improve her technique with her magical staff Raising Heart, observes Miyuki's solo training. Throughout the first season, Miyuki remains unaware of magic, although she finds out about Nanoha's powers at the end of A's.