The Maiden of Mio (Aqua), also known as the IPD Queen, is an IPD Reyvateil who holds the administrative privilege for the control over the Infel Phira, allowing her to access its most powerful functions, the most important of which is uniting the feelings of all the IPD Reyvateils into a single virtual singer and redirect the effects of EXEC_METAFALICA for the creation of the Heart of the Land to Infel Phira.
Due to her instrumental role in the creation of Metafalica, the Maiden of Mio was regarded as an important position alongside the Maiden of Homura (Fuero), who have Frelia's D-Cellophane and with it, the ability to sing EXEC_METAFALICA. Together, they were supposed to undergo the trials of Infelsphere in order to forge the bond needed for them to synchronize with each other in order to successfully sing the complete Metafalica.
However, after the The Pact of Hibernation, the Maiden of Mio has become known as the Maiden of Taboo, and the position was banned within the Grand Bell until Alfman reinstated the position as the figurehead for the War against the Goddess.
Historically, there are only two Maiden of Mio in existence. The first one is Infel, which was partnered with Nenesha, the 14th Maiden of Homura, and the current one is Cloche Leythal Pastalia, partnered with the 33th Maiden of Homura, Luca Trulyworth. While both pairs were able to complete the Infelsphere, Infel and Nenesha's attempt to create Metafalica was unsuccessful, causing Nenesha to be killed as the energy was taken from the Goddess. It was not until A.D.3774 that Cloche Leythal Pastalia and Luca Trulyworth were able to successfully create Metafalica, with a word of encouragement from Infel to the former.