Shinzo Watanabe

Age: 17 (12 from chapter 1, 13 at chapter 3.)
Nationality: American-Japanese.
Birthday: September 11th.
Birthplace: Los Angeles, California, United States.
Hair: Black.
Eyes: Sapphire blue.
Skin: White.
Physical complexion: Quite tall, thin but strong and piercing looking.
Personality: Good-willed, deep voice, honest, introversive and serious.
Blood type: O.
Fighting style: "The Hybrid" (A mix of karate, Hayabusa ninjutsu, judo, Jeet-Kune-Do and many ways of kendo, including kenjutsu [sword handling] and iaijutsu [death slash].)
Weapons: Vicious, katana sword; and Spike, Magnum Desert Eagle .50AE handgun.
Likes: Music, manga and anime drawing, digital art, playing any music instrument and the Chinese food.
Dislikes: Psychology, being lonely, any form of evil and lies.
Known relatives: Naomi Watanabe (mother, deceased at Shinzo's 16), Adrian Tenshi (father, deceased) and Yuna Tenshi (older sister [As you might guess, she's from Final Fantasy X].)
Favorite music: Drowning Pool, Linkin Park, Staind and a lot of rock music.
Favorite movie: Kill Bill (the two volumes.)
Favorite TV program: Cowboy Bebop.
Favorite book: Stephen King's The Green Mile and all of Tom Clancy's.
Favorite game: Quake.
Complex: A free soul samurai.
Statement: "I don't want to die... without knowing love. Without love I'm nothing."

Shinzo, the main character, is the son of the Watanabes, which comprises of mother and an older sister. At 12 he lost his father who left an unfinished war, which he will later participate. His life will change with the arrival of an Ainu girl, who will support him in any situation, and other events he will later discover.
He's a trained swordsman, a fearless fighter and a firearm expert, with very impressive skills. Due to the lack of magic powers, he carries a high caliber handgun, Spike, but he is rarely seen fighting without his sword, Vicious. He has nothing to lose and he will begin a battle against the forces of Hell, not only to save the world, but to protect what he considers important in life: his beloved ones.

Nakoruru

Age: 17 (12 from chapter 2, 13 at the outro.)
Nationality: Ainu-Japanese.
Birthday: October 11th.
Birthplace: Ainumoshiri Kamui-Kotan, Hokkaido, Japan.
Hair: Black.
Eyes: Black.
Skin: Bright white.
Physical complexion: Short-measured, thin, beautiful body and angel face.
Personality: Kind-hearted, soft-spoken, sweet voiced and a little shy.
Blood type: AB.
Fighting style: Shikanna Kamui Dancing Sword School and Shinzo's fighting style (She learned some moves from Shinzo.)
Weapon: Chichiusi, kodachi (kind of Ainu dagger.)
Likes: Talking with nature in her homeland, including its wildlife; music, the cherry blossoms, math and Galford (Yes, he will appear on my next fanfic!)
Dislikes: People who pollute nature and evil spirits.
Known relatives: Monashiri (grandmother), Sanouku (grandfather) and Rimururu (younger sister.)
Known companion: Mamahaha (hawk) and Shikuruu (wolf.)
Favorite music: Evanescence, Hybrid and all classical instruments ("They all sound beautiful, and make me feel at home".)
Favorite movie and book: The Lord of the Ring collection.
Complex: It's a secret.
Statement: "To protect nature, it's necessary to make some sacrifices."

Born in a family of maidens, Nakoruru is a descendant of the Ainu tribe. At 12, she travels to Tokyo by orders given by the Ainu chief, her grandmother, who predicted a terrible event that will involve her. She meets Shinzo in a harbor situation, but she saves her life and since then, they become very good friends. She considers him like her "Undercover Brother".
She learns how the life in the city is thanks to Shinzo. She has the power of the Holy Maiden and fights together with Mamahaha and Shikuruu, her beloved companions. And she is even able to sacrifice her life to save the world, though Shinzo doesn't like it.

Other characters:

Rika Sasaki and Naoko Yaganisawa (from Card Captor Sakura.)
Shinzo and Nakoruru's classmates.