The Chinjao Family (チンジャオファミリー, Chinjao Famirī) is a gang from the Flower Country, led by Chinjao Don. They are competing in the Corrida Colosseum for the Flame-Flame Fruit, but also have an ulterior motive.
Not much is known about what they do in Flower Country, but the two members seem to be very loyal to their leader, Chinjao Don.
Members of the family have a blood relationship with each other. Sai and Boo are the grandsons of Chinjao Don who is the head of Chinjao Family. All three of them are (or in Chinjao's case, was) in the Happo Navy, and specialize in the Eight-Impact Fist (八衝拳, Hasshō-ken), a fighting style that imbues vibrations in a strike to break the enemy's armor and weapons, similar to Whitebeard's Tremor-Tremor Fruit.
In the past, their leader was a fearsome pirate, worth over 500,000,000 berries. After Garp D. Monkey dented Chinjao's pointed head, robbing him of his power and the means to acquire his fortune, Chinjao swore to get revenge on Garp and his family.