Bikou

Bikou is a Monkey Youkai who is member of the Vali Team previously affiliated with the Khaos Brigade. He is a descendant of Sun Wukong and the current Monkey King.

Appearance
Bikou mostly seen in his human form, as a young man with short light-colored hair (Black in anime).

He's dressed in ancient Chinese armor that was used during the Three Kingdoms period.

Personality
He has a flippant and playful personality, who likes to joke around, with no elegance and obsessed with battles like Vali Lucifer. He also appears to laugh in a vulgar way like Kuroka (according to Fenrir).

History
As a member of Sun Wukong's clan, Bikou comes from the Mountain of Flowers and Fruit like his ancestors. He was given the title of the Monkey King at some point before the series but decided to leave the mountain and join the Khaos Brigade, becoming a member of the Vali Team.

Birth of the Breast Dragon Emperor
He appears in Volume 4 calling Vali to retreat.

He reappears in Volume 5 with Kuroka and tries to convince her to retreat but ended up fighting Tannin before the arrival of Arthur Pendragon.

In Volume 6, he and Vali appeared in front of Issei who had just finished his contract with one of his clients; with Vali warning him of Diodora Astaroth. He later reappears with Vali and Arthur to witness Issei's Juggernaut Drive and the Great Red, saving Asia from the Dimensional Gap. Before retreating, he coined both nicknames to both Issei and Rias, calling them the "Oppai Dragon" and "Switch Princess".

The Heroic Oppai Dragon
Bikou reappears in Volume 7, alongside the entire Vali Team (except for Le Fay Pendragon and Gogmagog) in a temporary alliance with the Gremory Team to battle Loki and Fenrir. He was also in shock and scared when he heard that his ancestor and the original Sun Wukong was currently looking for him, saying that he is a total monster despite his age.

In the beginning of Volume 12, Bikou and the rest of the Vali Team were hiding in the Gremory Palace in order for Vali to be healed by the original Sun Wukong. Later, he and the rest of the Vali Team, except for their leader, Vali, attacked the Grim Reapers at Hades' palace in the Realm of the Dead.

The Legend of Oppai Dragon and his Lively Companions
In Volume 15, Bikou appears alongside Vali, Arthur and Fenrir in Romania, meeting up with Azazel who was in Romania as well to discuss with Azazel about the re-emergence of the Evil Dragons, the Vampires, the Holy Grail and Euclid Lucifuge.

In Volume 16, Bikou, along with Arthur and Fenrir, battled with the possessor of the Longinus, Incinerate Anthem, and the magicians from Hexennacht. He later participated in the meeting for the formation of D×D and reminded Sun Wukong not to push himself too much.

Powers & Abilities
Senjutsu and Youjutsu User: While not at his ancestor or Kuroka's level, Bikou has stated that he is trained on using both Senjutsu and Youjutsu.

Transformation: Similar to his ancestor, Bikou has the ability to transform and is usually seen in his human form.

Immense Durability: Bikou was able to withstand Tannin's flame with little injuries (Tannin, however, was also holding back at the time).

Equipment
Ruyi Jingu Bang (如意棒 Nyoi-bō): A Golden staff that can extend and retract in size and length, and is named after the same legendary staff his ancestor used.

Jīndǒu Yún/Flying Nimbus(筋斗雲 Kinto'un): Bikou can summon a golden cloud similar to his ancestor that he can ride on.

Trivia

 * Bikou's height is 172 cm. (5 feet 8 inches), as stated in an issue of Dragon Magazine.
 * Bikou's name means "Beautiful Monkey", in reference to his monkey-like appearance, also refers one of the nicknames of the original Sun Wukong, Měihóuwáng (美猴王, "handsome monkey king", Bi-kou-ou in Japanese))
 * In the novels, Bikou is sometimes called Bikou Sun Wukong, meaning "Bikou the Monkey King".