Takei notes in an interview, that she is like his own personal mascot or good luck charm because Anna appears (albeit usually in cameos) in so many of his works.
She is depicted as a relatively thin girl with shoulder-length blonde hair who wears a short black dress, traditional sandals, and blue prayer beads she uses as an itako.
In response, Hao expresses interest in her, possibly because she resembles Asano-Ha, the mother of his original incarnation 1000 years ago, and because of the extent of her power.
Because she is certain of her assessment of his abilities, she rarely loses her composure when he is in danger unless something completely unexpected arises, such as when she believes Yoh was about to be killed while being possessed by Tokagero.
Yoh is constantly intimidated by Anna, seemingly fearing her wrath even more than Hao, though his feelings for her are expressed in how the promise he made to her to become Shaman King is the greatest motivation he has to continue fighting.
She could not help but pick up the negative emotions of others every time she was around other people; because of this, she began to hate others, and this hatred would involuntarily manifest itself as an Oni (demonic ogres, akin to boogeyman in Western cultures).
Yoh's positive influence on Anna allows her to gradually open her heart and she accepts his invitation to accompany him to a temple on New Year's Eve.
The Oh-Oni created gains the ability to speak and kidnaps Anna to take her to Mount Osore to absorb the lurking spirits there.
Because Yoh freed her from the darkness that haunted her each day, she grows to love him and resolves to become stronger so as not to feel the same pain in the past and to repay him for everything he sacrificed for her.
Anna appears in Takei's short story Funbari no Uta; she has a son named Hana Asakura and she is married to Yoh.
She wields the sword Harusame (which would reappear in Shaman King as a primary medium for Amidamaru) and expresses an interest in traveling to find her birth parents.