Miang: Mother of humanity. Host body: Boyfriend Ramsus.
Spoiler - Miang is part of the Deus weapon system who gave birth to the first humans in Xenogears. Miang transmigrated throughout the history and "jumped" from woman to woman. The current Miang is an element working under Kahran Ramsus command. She is secretly manipulating Ramsus and has no other will but to resurrect Deus.