These are the byakko seishi and miko who we never really met in the 52 part tv series or the OVAs. Little is known about them, although Watase-sensei is thinking about writing out their stories sometime in the future.
Name: Oosugi Suzuno
Pronunciation: oh-sue-gi sue-zoo-no
Seiyuu : Nakazawa Midori
Suzuno was Byakko No Miko almost one hundred years before Miaka and Yui's time. By that time, Suzuno is very old and dying, this is how Keisuke and Tetsuya find her.
***SPOILER WARNING*** (for tv ep. 43)
It is explained that Genbu No
Miko's father was a close friend of Suzuno's father, Oosugi Takago,
and upon Takiko's death intrusted the book to him as it could not be
destroyed. It was this way that Suzuno found the book and entered it as
Byakko No Miko. Due to Suzuno's strong sense of will, she was not devoured
by the animal god after merging with Byakko, as Takiko was. Upon her
death, she is reunited with her love Tatara
who was one of her seishi in the Universe of the Four Gods.
and, i also have a better pic of suzuno, from the 1st artbook:
Star Pattern: Aries
Seishi Name : Kokie
Pronunciation: ko-kay
Character: Stomach
Star Pattern: Taurus
Seishi Name : Ameturi
Pronunciation: a-meh-tu-dhe
Character: Rain net
Star Pattern: Orion
Seishi Name : Karasuki
Pronunciation: ka-dha-ski
Character: Investigator
Star Pattern: Orion
Seishi Name : Toroki
Pronunciation: toe-roe-key
Character: Turtle snout
Although never shown in the anime or manga, Ryoko sketched a pic of her interpretation of Toroki