Beasts Pirates

The Beast Pirates are a pirate crew ruling in the New World, led by the Yonko Kaido.

Past
At some point in the past, Kaido formed the Beast Pirates. Sometime within the last four years, they formed an alliance with Donquixote Doflamingo and Caesar Clown in order to gain an army of artificial Zoan Devil Fruit users.

Marineford Arc
Upon hearing that the Whitebeard Pirates were headed to Marineford, the Hundred Beast Pirates tried to intercept them so their captain could kill Whitebeard. However, they were stopped by the Red Hair Pirates.

Dressrosa Arc
Led by Jack of the three Disasters, several of the Beast Pirates entered Zou to search for Raizo the ninja. They came into conflict with the Mink Tribe, who easily beat back the Pleasures and initially held the advantage. However, Jack used Caesar's poison gas weapon to overwhelm the minks and destroy the Mokomo Dukedom, sending Duke Inuarashi into a coma.

The search continued for several days as the Straw Hat Pirates led by Sanji entered the island and came into conflict with the Hundred Beast Pirates. The Straw Hats managed to defeat Sheepshead, the leader of the Gifters, and the pirates following Sheepshead retreated. It is unknown what became of them, though it was hinted that the Straw Hats warded them off.

While this happened, other members of the Beast Pirates received word that Donquixote Doflamingo had fallen. Meanwhile, Kaido attempted suicide by jumping off a Sky Island and landed on the Kid Pirates base. He survived the fall and prepared to have Doflamingo help him start the greatest war in the world.

Jack left Zou to go rescue Doflamingo from incarceration and attacked the Marine convoy that was escorting him. Though he succeeded in sinking two of the ships, Jack was eventually brought down and reported as dead, though his body was not found.

Jolly Roger
The crew's Jolly Roger is a skull with a bone in the middle of a pair of crossbones. The skull has horns similar to Kaido's.

Organization
Kaido, the captain, has full control over the crew. At his side are three beings known as the Disasters (災害). One of them, Jack, has the ability to become a mammoth, granting him immense size and strength. Jack has authority over the Gifters and Pleasures.

One division of the Hundred Beast Pirates is called the Gifters (ギフターズ), a group lead by the Headliner Sheepshead. All the Gifters have animal traits.

Another division is the Pleasures (プレジャーズ), who resembled foot soldiers and do not appear to have any animal traits. Not much else is known about their strength, except that for some reason, they are always smiling, even when they receive damage and in pain.

Crew Strength
The Beast Pirates are led by the Yonko Kaido, making them one of the four most powerful pirate crews in the world. Donquixote Doflamingo, a former Shichibukai and the leader of an incredibly powerful pirate crew of his own, who usually maintains a fearless attitude was deeply scared of Kaido. They attacked the Whitebeard Pirates in the hope of killing Whitebeard, something few would dare, and took on the Red Hair Pirates. They were stated by the Gorosei to be one of the few entities capable of stopping Blackbeard and his crew. During the timeskip, they formed an alliance with the Drake Pirates, a crew from the Worst Generation. They were also responsible for defeating Moriah and his crews.

Like the other Yonko, the Hundred Beast Pirates possess territory in the New World, and they have been shown to rule with an iron fist and put a stop to any insurrection.

The true strength of this crew lies in their Underworld connections. Due to Kaido's alliance with Donquixote Doflamingo and Caesar Clown, they had access to SMILEs to help form an army of over 500 artificial Zoan Devil Fruit users. They also have access to Caesar's poison gas weapons, which they used to destroy a city of minks.

Trivia

 * The crew seems to have a card games theme with Sheepshead and Ginrummy with Jack and Scotch being a reference to Blackjack (or simply the Jack playing card rank) and Catch the Ten (also known as "Scotch Whist") respectively.
 * This is the fourth card-themed crew after Spade Pirates, Donquixote Pirates and the non-canon Trump Siblings.