The princess of the Tokugawa clan.
She's Muneakira childhood friend and she shows feelings for him. She then reveals her feelings, and kiss Muneakira, becoming his third Samurai Master. Her weapon is a naginata decorated near the blade, and her transformation phrase is "Tenga Ryūrei", which means "Elegant Beauty". Sen's attacks usually revolve around thunder or lightning. She has a friend (or a ninja maid) named Hanzou Hattori.
She's voiced by Minako Kotobuki.