(*Note: This is an in-game legend and has no historical parallels)
Maihime Amano is a beautiful princess knowledgeable in the art of magic, and lover of the prominent samurai Tatsunoshin Suou. She assisted in her beloved's plan to assassinate the feudal warlord Kiyotada Sumaru along with Junnosuke Kuroda, but Sumaru managed to kill her with a spear, causing the move to end in tragic failure.
If Maya obtains and spreads the rumor of the existence of Maihime Amano's mummy from Setsu Nishitani (the old lady in Araya Shrine), she will appear later on at Sumaru Castle 7F and can then be summoned as a Persona of the Moon Arcana in Velvet Room without the need of Material Card. Along with Tatsunoshin Suou and Junnosuke Kuroda, they can cast a Fusion Spell capable of instantly destroying Kiyotada Sumaru's Gozen form in a single blow.
Even though Maihime Amano has only two skills, her first skill, Affectionate Prayer, is extremely valuable because it does double duty to heal the party in battle and be used in Fusion for any type of stat boost (-kaja) spell which targets the whole party. Of the other two Personas with Affectionate Prayer, Priestess Izanami (level 51) requires Material Card to be summoned, and Fortune Gyokukou Joutei is level 77 which is much higher than Maihime's 54.
Before entering Sumaru Castle, the player obtains and spreads Tatsunoshin Suou's rumor from Akinari Kashihara in Kismet Publishing, then obtains and spreads Maihime Amano's rumor from Setsu Nishitani in Araya Shrine. Find Maihime's mummy at 7/F in Sumaru Castle and she will be summonable in the Velvet Room.