Shiki Granbell's travels upon the Eden Zero would not have gotten very far without the help of Xiaomei. Journeying across the Cosmos, Shiki Granbell and the Edens Zero Crew are focused on finding the location of Mother so that all their wishes can come true.
The Crew's space exploration and time-traveling can become rather confusing, but Xiaomei provides viewers with guidance and insights as she narrates the show. However, as a resident of Mildian, the Planet of Time, this omniscient knockout has a distinct air of mystery about her, as if she knows much more than she is letting on.
The "Legendary Fortune Teller"
This sci-fi Anime would not be the same without the contributions of Xiaomei, who possesses more power than the average human, having been blessed with skills of premonition (and possibly time travel as well). She has an omniscient aura around her, almost God-like but not quite, and never gives a straight answer - often influencing more questions than answers. As the narrator, Xiaomei loves to drop titillating hints throughout the show, addressing the audience directly to remind them that time holds little value, or that things are about to get exceedingly violent.
As fans become more familiar with this ethereal character, they realize that Xiaomei is more than just an observer when she finally meets the Edens Zero Crew in the Mildian arc, when Shiki and his friends wish to consult the Time Oracle about Valkyrie's whereabouts. Staying true to her character, Xiaomei does not simply provide the answer but instead sets up a series of elaborate battles cloaked in layers of deception. With a personal, perverted investment in the fighting, the fortuneteller throws more and more opponents at Shiki and the Crew until finally, Valkyrie herself appears when Homura steps into the ring. It is soon revealed that Homura's opponent is an imposter, and Xiaomei eventually provides the Crew with the true location of Valkyrie - yet again leaving out crucial details - the fact that Valkyrie had died.
Although Xiaomei appears to get a thrill out of conflict and playing mind games, she does not seem to be a villainous character - as frustrating as she may be. Many viewers feel that the Fortuneteller could have provided the Edens Crew with further information regarding their past, present, and future and alleviated a lot of pain and suffering in the process. However, as someone with a broader concept of how time works, Xiaomei is undoubtedly aware of the negative repercussions of dabbling with time. The more information that she provides Shiki and the Crew with, the more she interferes with fate and, although she may be saving them a moment of hardship, the ripple effects could be disastrous. Viewers, however, are far removed from the situation, so as a narrator she could at least dish out more details to the audience!
Mother, the Goddess of the Cosmos
This cyan-haired beauty is believed to exist beyond the Sakura Cosmos, and those lucky enough to find Mother are granted a wish and are subsequently reborn (although it is unclear whether this refers to reincarnation or a spiritual awakening). There seems to be a strong link between Shiki and Mother, who the young explorer claimed to have met when he first laid eyes on an image of the Goddess at the Shooting Starlight Guild Headquarters. The other Adventurers ridiculed Shiki because, as far as anyone is concerned, no one has encountered the omnipotent entity before - unless perhaps their memories were wiped, and they cannot recall the encounter.
The most popular opinion concerning Xiaomei's origin suggests that she was once a human Adventurer who was lucky enough to find Mother. Her wish likely focused on the pursuit of knowledge, which would explain her powers of premonition and omniscient qualities. Many fans believe that when she was reborn, Xiaomei lost the memories of her past life and proceeded to settle on Mildian, the Planet of Time, as the master of her own little Universe.
Family Matters
Some fan theories go so far as to suggest that Xiaomei could in actual fact be Shikki and Rebecca's daughter, conceived a few years before the couple found Mother and were reborn themselves, 30 years later, where the Edens Zero storyline takes off. Due to the memory loss of rebirth, the pair had no knowledge of their daughter, who was subsequently raised elsewhere, only to be reunited with her parents years later.
Their relationship could explain why Xiaomei seems so invested in Shiki's story, intervening in situations even when she knows it's best not to and carefully watching their progress through the Cosmos. Xiaomei would have also lost her memories during rebirth, but maybe her powers of omniscience alerted her to the fact that she is Rebecca and Shiki's daughter. There is a large consensus among viewers that Shiki is a direct descendant of Mother herself and, if Xiaomei is in deed the Adventurer's offspring, she too would be related to the Goddess.
Immortality
It has been speculated that the all-powerful Xiaomei may be living an everlasting life, however, this immortality may be conditional. Because Mildian exists in its own time plane, separate from the rest of the Universe, its occupants will never age since time stands still.
It is therefore uncertain if her immortality is explained by her current location, or if it is another one of Xiaomei's powers. It seems that fans will only know for sure if the Legendary Fortuneteller leaves the planet of Time one day.