They Are My Noble Masters - Season 1 Episode 7 Kuonji Household Annihilation!? The Client was Ageha-sama!

Accompanied by her troop of loyal soldiers, heiress to the Kuki Conglomerate and friend of Yume, Ageha Kuki, arrives at the Kuonji household. Ageha frequently engages in vigorous martial arts training with her servant Kojūrō, but after he accidentally fell down a waterfall after a particularly active session her father decided to send Ageha to the Kuonji household to learn self-restraint. After having the mansion cleaned up and offering gifts to the Kuonji women, she begins to train with Ren. Ren throws himself in front of Ageha to save her from an assassin's dart, and even though this proves unnecessary as Ageha was able to grab the dart herself she rewards his loyalty with a kiss.