tsukiumi

Height: 165cm
Weight: 47kg
Sekirei No: 09
Three sizes: B 94 / W 57 / H 88
She is Minato's fourth Sekirei, and her power is water, derived from her name "umi," which means the sea. Initially, she contacted him through a dream, threatening to kill him. However, upon their meeting, she was convinced to become his Sekirei. (Chapters 22-23) Tsukiumi claims to be Minato's legal wife. At first, she aimed to be the strongest to prove that Ashikabi were unnecessary for victory. Later, she confided in Miya that her true goal was to grow stronger to protect and live with her Ashikabi forever.
Tsukiumi has a tsundere personality and is the most aggressive among Minato's Sekirei, with a very short temper; she seldom smiles. She was introduced as the first Sekirei who sought to become the strongest without an Ashikabi's help. She even declared she would kill her future Ashikabi if she reacted to them, due to her disdain for Ashikabis. After being winged by Minato, she changed significantly and becomes easily jealous when Minato interacts with other women, driven by her feelings for him. Proclaiming herself as Minato's legal wife sparked rivalry among his other Sekirei, particularly Musubi, with whom she frequently competes for the title of 'Minato's legal wife.' Despite this, she gets along well with Minato's other Sekirei.
(Source: Wikipedia, Sekirei Wikia)