My intention in this section is to give you a very brief overview on each character. For those of you who have never seen or read the series, I hope that the illustrations give you a fair idea of what each character looks like and their personalities.  Unfortunately, I was unable to give you a picture of some of the characters mentioned below. If I do get a picture, I will be sure to add them in. The Genbu and Byakko Seishi were barely elaborated on because they didn't really have a big role throughout the series except for a minor few of them.

This section is spoiler free.

Main Priestesses

Yuuki Miaka
She's the Priestess of Suzaku. She along with her best friend Yui, were pulled into the Universe of the Four Gods.

Hongo Yui
She's the Priestess of Seiryu, Miaka's best friend.

Suzaku Seishi

Tamahome
He was the first Suzaku Seishi to be found making his appearance in the first episode. He's the leading male character of the show and the love of Miaka. His Seishi character is "oni"-Ogre, which is located on his forehead. His Seishi power makes him a good fighter and he is skilled in martial arts.

Hotohori
Hotohori is the Emperor of Konan Country. He fell deeply in love with the Priestess and vied for her affections. His Seishi character is "sei"-Star, which is located on his neck. His Seishi power makes him highly skilled in swordsmanship.

Nuriko
Nuriko is first introduced as one of the princesses living in Hotohori's palace. His Seishi character is "yanagi"-Willow and can be found on the left side of his chest. His Seishi power is Superhuman strength.

Chichiri
Chichiri is known as the masked monk who made an interesting entrance during the series. He is the rock of the group, the one that holds everyone together. His Seishi character is "sho"-Well, which is located on his knee and his Seishi power is polymorphing. He also learnt magic from Taiitsukun.

Tasuki
Tasuki was the fifth Suzaku Seishi to be found and is a member of the Mt. Leikaku bandits. His Seishi character is "yoku"-Wing and can be found on his foreham. His Seishi power gives him the advantage of great speed. To learn more on Tasuki, you can read all the information located in the shrine.

Mitsukake
Mitsukake is the gentle warrior with the broken heart. His Seishi power is healing.

Chiriko
The youngest of all the Suzaku Seishi and the last to be found, or rather he found them. His Seishi power grants him extreme intelligence.

Seiryu Seishi

Nakago
Nakago is the shogun of Kutou country and the strongest of the Seiryuu Seishi. His seishi character is "shin"-Heart and is located on his forehead. His Seishi power allows him to manipulate chi.

Ashitare
Ashitare is the most unusual of the Seiryuu Seishi. He seems to be half-man, half-wolf. His Seishi character is "bi"-Tail and is located on the right side of his lower back. His Seishi power grants him the ability to change into a wolf.

Soi
Amongst the men, she's the only female Seiryuu warrior. Her Seishi character is "bo"-Tassel and is located on her left upper thigh. With her Seishi powers, she can control weather, electricity and various sexual techniques.

Tomo
Tomo is known for his unique, artistic dress and face painting. His Seishi character is root and is located on the lower right side of the pelvis. With his Seishi power, he can cast illusions especially using a "shin" (a hard clam).

Amiboshi
He is the twin brother of Suboshi and the gentler of the two. His Seishi character is "ko"-High Spirits and is located on the right shoulder. His Seishi power allows him to focus chi through the mouth using a flute.

Suboshi
Suboshi is the hot-headed twin, the bolder of the two. His Seishi character is "kaku"-Angle and is located on the left shoulder. His Seishi power is telekenesis, which he uses to control his weapon, the ryuuseisui.

Miboshi
Miboshi made his entrance throughout the last stages of the Fushigi Yuugi series. His Seishi power allows him to possess people's bodies and summon monsters. His Seishi character is basket.

Genbu Seishi

Tomite
His Seishi character is Emptiness and is located on the left side of his back. His Seishi power involves controlling ice.

Hikitsu
His Seishi character is "to"-Ladle and is located on the right eye. His Seishi power also involves controlling ice.

Iname
Iname's Seishi character is Cow. Seishi power unknown.

Uriku
Uruki's Seishi character is Woman. Seishi power unknown.

Urumiya
Urumiya's Seishi character is Roof top. Seishi power unknown.

Hatsui
Hatsui's Seishi character is Encampment. Seishi power unknown.

Namame
Namame's Seishi character is Wall. Seishi power unknown.

Byakko Seishi

Tatara
His Seishi character is Lasso and is located on the back of his right hand. His Seishi power allows him to control plants.

Tokaki
His Seishi character is Stride and is located on his left cheek. His Seishi power is the knowledge of pressure points and teleportation.

Subaru
Subaru is Tokaki's wife. Her Seishi character is "ko"-Rise and is located on the left breast. Her Seishi power allows her to manipulate time.

Kokie
Kokie's Seishi character is Stomach. Seishi power unknown.

Ameturi
Ameturi's Seishi character is Rain net. Seishi power unknown.

Karasuki
Karasuki's Seishi character is Investigator. Seishi power unknown.

Toroki
Toroki's Seishi character is Turtle Snout. Seishi power unknown.

Other TV Characters

Kajiwara Tetsuya
He is Keisuke's best friend.

Yuuki Keisuke
He is Miaka's older brother and only sibling.

Sou Yuiren
She is the youngest of Tamahome's siblings.

Sou Chuei
Chuei is Tamahome's younger brother, the second child of the family.

Sou Shunkei
Tamahome's other younger brother.

Sou Gyokulen
The older of his two sisters, she is yet another one of Tamahome's siblings.

Kouji
Tasuki's best friend.

Shouka
Mitsukake's late girlfriend.

Eiken
The Mt. Leikaku bandit who tried to overthrow Tasuki from his position as leader.

Tama
The cat usually in the company of Mitsukake.

Cho Kourin
She was Nuriko's little sister.

Kaika
The adopted son of a couple living in Bakan Village in Sairou Country.

Aono Tomo
Aono is the boy Miaka secretly falls for in her school while under a spell created by Tomo.

Toki
He is the adopted grandson of Suzuno, the once Priestess of Byakko.

Houki
... (anything I say will be a spoiler).

Nyan Nyan
They are the girls that live on Mt. Taikioyoku with Taiitsukun. Their bodies can be used as recepticals for spirits of the dead.

Taiitsukun
Taiitsukun is the creator of the Universe of the Four Gods.

OVA Characters

Gyoshuku
He is Hotohori's great grandson.

Kaen
...

Tenkou
He is the villain of the Fushigi Yuugi OVA series.

Sukunami Taka
He is the reincarnation of Tamahome.

Shigyou Ren
He is Mirru's brother and was introduced as a new student at Miaka and Yui's school.

Boushin
Hotohori's son.

Kamishiro Miiru
She is Ren's sister and was introduced as a student at Keisuke and Tetsuya's college.

Hikou
Hikou was Chichiri's best friend.

Yosui
... (I don't want to reveal spoilers)

Mayo
The young girl who rebelliously plunged into the Universe of the Four Gods to break up Taka and Miaka.