Jack "the Drought" is a member of the Beasts Pirates. He is one of the Three Disasters, Kaido's right hand man, and the captain of the Mammoth.  He also has ties with the Underworld. He was first briefly mentioned being notified of Caesar Clown's capture from viewers of Caesar's broadcast of the Punk Hazard incident.
Jack is a man of large stature. He wears a metallic jaw mask and a pair of horns on each side of his head. His hair is worn in a ponytail style along with a pair of long braids. He wears a sleeveless, feathery coat and a belt with his crew's Jolly Roger that goes around said coat as well.
He also has bloodshot eyes and a veined forehead. He has two piercings on his right ear and wears spiked pauldrons on his shoulders. He carries a pair of tusks around his neck that are actually sheathes that contain his scythe-like blades.
Jack is horrendously violent, fearsome, and short-tempered, as one of his subordinates worried how Jack would react once he learned about Caesar Clown's downfall. He threatened to destroy an entire city should he not get what he wanted, and made good on his word, saying that it's their own fault because they didn't comply. His ruthlessness extends to even attacking children and the elderly. He has even admitted that he has a love for causing destruction, even when there's no real benefit to it. Some people who have met him even describe these traits as insanity.
He is also rather sadistic, not being above torturing enemies in order to get what he wants. He is barbaric and merciless to the point of hacking off limbs and creating terrible bloodshed, only ceasing his carnage when he had more urgent matters to attend to. He is cruel to the point that he continuously tortures his captives for information even if it is obvious that they do not have it.
He is stubborn and unreasonable like his superior Kaido, as seen when the minks tried to tell him that Raizo wasn't on Zou, but he refused to listen or believe them and even refused when Inuarashi offered to let him search the island without any resistance to see for himself. This, along with him disregarding his crew's comment that attacking Doflamingo's convoy was dangerous, shows that he refuses to listen to logic. He takes this to a point where he actually becomes enraged when someone tries to reason with him, having no patience for civil conversations. Jack's lack of reason makes him very headstrong and reckless, as he decided to attack four Marine ships at once, which were carrying powerful Marines, to rescue Doflamingo.
He is not above fighting dirty, as he brought in Caesar Clown's gas weapon to annihilate Zou after the minks put up a formidable fight against his forces.
Jack does not appear to care about titles or fame, as he got annoyed with his subordinates for boasting about his position and bounty.
As one of the three Disasters, Jack has authority over the Gifters and Pleasures, who are incredibly loyal to him. Whether Jack respects his subordinates or not is largely unknown, but he does seem to become annoyed with them at times, as seen when they mentioned his bounty to the minks. He has also been shown to put them in unnecessary danger, as he ordered them to attack the powerful minks when they could have entered peacefully. However, his subordinates also seem to love battle and did not have any protesting opinions. They to be very proud of Jack's reputation and bounty, ranting about it to the Mink Tribe.
Via his captain Kaido, Jack is allied with Doflamingo, and was willing to retrieve the former Shichibukai from the Marine convoy carrying him, despite the heavy security. It was because of Doflamingo's defeat and capture that Jack left Zou before he could completely destroy what was left of the island.
It is unknown what Jack's relationship is to Raizo or why he wants to find him, but it can be implied that there is some importance between them, as Jack went so far as to reduce a country to rubble just to find Raizo.
Abilities and Powers
Being one of Kaido's right-hand men, Jack has authority over the Gifters, Pleasures, and anyone of lesser rank than him. His epithet is named for the fact that when he rampages on an island, it is left in a decaying state like it is suffering a drought. He has a bounty of 1,000,000,000, indicating that he is extremely powerful.
He has near inexhaustible strength and endurance, being able to fight on par with the Mink Tribe for five days and five nights without taking a break, even though the Minks switched fighters every twelve hours. Although the Minks were able to gain the upper hand, they were never able to suppress Jack himself.
He was able to sink two of the four Marine battleships that were part of Doflamingo's escort, but was no match for the entire fleet carrying Vice Admirals Tsuru, Bastille, Maynard, Admiral Fujitora, and former Fleet Admiral Sengoku.
Jack wields two blades which he uses when in his human form. He keeps them hidden and sheathed as the tusks around his neck. Though they resemble Shotels when seen 2-dimensionally, 3-dimensionally they are even more twisted, similar to his mammoth tusks. 
Jack had access to Caesar Clown's poison gas weapon during his invasion of Zou. He used its power to overwhelm the minks and destroy Kurau City.
Seventeen days before Luffy and Law's arrival at Zou, Jack and his men broke through the gate to the Mokomo Dukedom, leaving it in ruins and severely injuring the guards. Jack and Sheepshead then told the minks to hand over a ninja known as Raizo. The minks were unable to comply, causing Jack to get exasperated and destroy several buildings with his trunk. As the minks still were unable to disclose the location of Raizo, Jack ordered the Pleasures to lay waste to the countries. However, the minks easily fended them off with Electro, and Monjii warned Jack that every mink was a natural-born warrior ready to fight. The mink asked Jack to talk with the duke, but Jack refused as he ordered the Gifters to attack.
As Jack's subordinates were battling the Musketeer Squad, Duke Inuarashi arrived to confront Jack. Inuarashi tried to reason with Jack, saying that he would be allowed to search for the ninja if he ceased the destruction. Jack responded by attacking Inuarashi with his trunk, but the latter easily blocked the strike. Jack and Inuarashi clashed until 6pm arrived. After Inuarashi and his group left the battlefield, Master Nekomamushi arrived to challenge Jack. After he was slammed into the ground, Jack returned to human form, preparing to continue the fight.
The battle against the Mink Tribe lasted for five days, with Inuarashi and Nekomamushi's forces taking turns fighting with each passing day and night. Even though the minks had the upper hand against Jack's continuous forces, they were unable to overwhelm Jack himself. On the fifth day of the battle, Jack lost patience and brought in one of Caesar's poison gas weapons and claimed victory. With the Mink Tribe rendered helpless, Jack tortured the strongest of them for information concerning Raizo, taking a leg from Inuarashi and an arm from Nekomamushi. The following day, Jack heard about Doflamingo's defeat and capture. Jack promptly left Zou to rescue him, leaving behind some of his subordinates.
A few days later, Jack tailed the four Marine Ships that were escorting Donquixote Doflamingo to Impel Down. Despite warnings that powerful Marines were guarding him, Jack refused to leave and prepared to attack the Marine ships.
After the attack on Doflamingo's Marine escort, it was reported that Jack succeeded in sinking two of the ships, but ultimately fell to the Marines. However, the news was unable to completely confirm his death.
- Beasts Pirates vs. Mink Tribe and Heart Pirates
- Jack vs. Doflamingo's Marine escort (not shown)
- Jack has the highest known bounty in the series at 1,000,000,000, almost double that of Portgas D. Ace's 550,000,000, the previous holder of the highest known bounty.
- It is also the first known bounty in the series to exceed nine figures.
- Following the theme of his subordinates Sheepshead and Ginrummy, Jack's name is an allusion to the card game "Blackjack", as well as the "Jack" rank of a playing card, a trait shared with "Joker".
- Jack shares his name with "Calico" Jack Rackham, a notorious pirate in the early 1700s.
- ↑ 1.0 1.1 1.2 1.3 One Piece Manga — Vol. 80 Chapter 801 (p. 10-11), Jack makes his first appearance.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 One Piece Manga — Vol. 81 Chapter 808.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 One Piece Manga — Vol. 81 Chapter 809.
- ↑ One Piece Manga and Anime — Vol. 70 Chapter 692 (p. 5) and Episode 618, Jack is first mentioned by one of his subordinates
- ↑ 5.0 5.1 5.2 5.3 One Piece Manga — Vol. 81 Chapter 810 (p. 2-10), Jack fully shows his face, and tortures the defeated Minks.
- ↑ 6.0 6.1 6.2 6.3 One Piece Manga — Vol. 80 Chapter 806.
- ↑ One Piece Manga — Vol. 81 Chapter 808 (p. 10), Jack refuses to speak peacefully with Inuarashi.
- ↑ One Piece Manga — Vol. 81 Chapter 807.
- ↑ One Piece Manga — Vol. 81 Chapter 810.