Recently (2004), Watase-sensei began producing the Genbu Kaiden story, illustrating Okuda Takiko's entry into the Universe of the Four Gods and history. I'll try to update this page with more information from the manga series, as I get them.

Name: Okuda Takiko
Pronunciation: oh-ku-da ta-key-ko
Age: 17
Seiyuu : Tanaka Atsuko
Takiko was Genbu No Miko two hundred (book) years before Miaka and Yui's time.
***SPOILER WARNING*** (for tv ep.42?)
When Takiko called Genbu, she merged with him so
as to be able to use his powers. After using the three wishes, she was
returned to Japan, dying and in much pain. Not wanting to see his
daughter in so much pain, Takiko's father, Okuda Einosuke tranlator of
the ShiJinTenChiSho, killed her to give her peace. It was this "crime of
love" that Keisuke and Tetsuya found in the library to lead them to Oosugi
Suzuno.
Genbu Kaiden Manga info
Takiko is a spirited girl of the Taisho era. She is intelligent and
proficient with a naginata. She lives with her ailing mother and
governess, while her father is often away traveling on research trips.
For years Takiko has harbored both a growing hatred for her father and a
love for her father's friend, a young scholar named Ohsugi. Upon his
return from Cathay (China), Okuda Einosuke spends his time, not with his
sick wife or daughter, but with his recent translated work entitled, "The
Universe of the Four Gods." It was then that Takiko's mother passed on.
Takiko is furious that her father was not there with his wife, and runs
from the house to be found by Mr. Ohsugi. In her despair, Takiko
professes her love for Ohsugi, who as a husband and father, denies her in
return. Running from her shame, she finds her father and focuses all her
anger and frustration on him, grabbing his precious manuscript and begins
to tear it. Suddenly a silver light shines from the book, some snow
appears and Takiko is gone.
Star Pattern: Aquarius
Seishi Name: Uruki
Pronunciation: u-rue-key
Real Name: Limdo
Seishi power: Control of Wind, changes into a female
Character: Woman
Location of Character: Middle of chest, between breasts
Genbu Kaiden Manga info
Limdo is a young man and a dangerous criminal. Lindo is a proficient
fighter who uses a bladed disc on a tether and wind magic. When he uses
his powers, his seishi symbol appears and he changes from a man into a
woman. (I am beginning to think the wind power can be used independant of
the sex change power) As such, he takes no especial pleasure in the naked
female form...which he nonchalantly informs Takiko (who had freaked when
the fevered young woman she had been helping get warm turned into a
man).
***SPOILER WARNING*** (for chapter 6 of manga vol.2)
In chapter 6, Soren, Limdo's servent reveals to
Takiko, Tomite, and Hatsui that Limdo is the son of the Hokkan Country
Emperor. The ShiJinTenChiSho for Hokkan said that when the Miko appeared,
the Emperor's son would surely kill the Emperor. So, the Emperor ordered
his son killed. His mother entrusted him to her family's loyal servants,
Tawur (chinese translation) and his son (Soren). Tawur raised Limdo as
his son alongside Soren. Around age 11, assassins found Tawur and the boy
prince. Tawur was killed and Limdo's seishi powers manifested. His
father continues to send assassins.

Star Pattern: Pegasus
Seishi Name: Hatsui
Pronunciation: ha-t-swe
Real Name: Zaraa
Seishi Power: Can enclose self in metal sphere and shoot physical
manifestations of needles.
Character: Encampment
Location of Character: Currently unknown
Hatsui was shown with who i think is Urumiya in OVA1 #2&3. Hatsui is a boy with dark brown hair. {thanks to Gail for capturing this pic for me}
Genbu Kaiden Manga info
Hatsui is a chubby young boy with dark hair up in buns. It seems that
he's been pushed around his whole life, unappreciated and unloved.
Takiko convinces him to join her with promises of acceptance and
friendship. Hatsui can project thousands of needles from his body. He
is very good at directing where the needles go...being able to avoid
friends who are around him while still hitting his intended targets.
Star Pattern: Pegasus
Seishi Name : Namame
Pronunciation: na-ma-meh
Seishi Power: Can grow in size and mass and can meld with stone
Character: Wall
Location of Character: On face (actually, the characters form his
face)
Found in the Genbu Kaiden manga volume 3, Namame was born of the native rock of Hokkan, and as such, looks like a little rock person. He(?) can use his powers to grow in size and mass to become a huge rock creature, or any other rock form he wants, including melding with the rock itself. He does not speak verbally, but telepathically.
Star Pattern: Capricorn
Seishi Name : Iname
Pronunciation: i (as in fish) nah-meh
Character: Cow

Star Pattern: Aquarius
Seishi Name: Urumiya
Pronunciation: u-room-ya
Character: Roof top
As close as i can tell, it was Urumiya who was with Hatsui in the OVA1 #2&3. if so, Urumiya had white hair and was a boy. {thanks to Gail for capturing this pic for me}