Jack the Drought is a prominent member of the Beasts Pirates, one of Kaido's three right-hand men known as the "Disasters", and the captain of the Mammoth. He also has ties with the Underworld. Due to his actions, he is the main antagonist of the Zou Arc and is one of the central antagonists of the Yonko Saga. He was first briefly mentioned when being notified of Caesar Clown's capture by viewers of Caesar's broadcast of the Punk Hazard incident. Jack is a man of massive stature, dwarfing his crewmates and even the very large minks Inuarashi and Nekomamushi. However, while still being immensely muscular, Jack's arms are disproportionately small when compared to his enormous torso. He wears a metallic jaw mask (though despite that, when in his mammoth form, he does not wear it) and a pair of horns on each side of his head. His blond hair is worn in a ponytail and a pair of long braids. He wears a dark, sleeveless, feathery coat similar to Kaido with spiked pauldrons on his shoulders, circled by a belt bearing his crew's Jolly Roger.
When using Koro on the Minks, he wears a hazmat suit and wears a glass helmet around his head. He has bloodshot orange eyes and a veined forehead. He has two piercings in his right ear, and wears spiked pauldrons on his shoulders. He carries a pair of tusks around his neck which are actually sheathes containing his scythe-like blades. His mouth contains pointed teeth but while in his mammoth form he has square teeth. Jack is violent and short-tempered, as one of his subordinates worried how Jack would react once he learned about Caesar'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 was the citizens' own fault because they did not 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 is no real benefit to it. Those who have witnessed Jack's personality in person describe these traits as madness. He is also extremely sadistic, willing to torture enemies in order to get what he wants. He is barbaric and brutal to the point of hacking off limbs and creating terrible bloodshed, only ceasing his carnage when he has more urgent matters to attend to. When Jack attacked the giant elephant Zunisha, he was determined to get to its head and came up with several horrendously cruel things he and his underlings could do to kill it. He is extremely stubborn and unreasonable; when the minks tried to tell him that Raizo was not on Zou, Jack refused to listen to or believe them, and continued to refuse 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, proves that he refuses to listen to logic, to the 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 a convoy of four Marine ships, which were carrying powerful Marines, to rescue Doflamingo. He is not above fighting dirty in order to achieve his goals, as he brought in Caesar's gas weapon, Koro, to annihilate Zou after the minks put up a formidable fight against his forces, simply because he was losing his patience and not because he was in any actual danger of losing. He is also strategic, and desires to use the most effective methods possible to win; upon his return to Zou, he decided to outright kill Zunisha, the elephant carrying Zou, to destroy the country in the quickest way he could and avoid having to fight the minks again while ensuring they were finished off for good. Jack is very thorough in battle, wanting to make sure his opponents are completely annihilated and presuming that they will return to full strength otherwise; additionally, he does not tolerate it when his subordinates fail their missions, having brutally punished Sheepshead for not finding Raizo. Jack does not appear to care about titles or fame, as he got annoyed with his subordinates for boasting about his position and bounty. However, he is still prideful, as he got angry when he read the news report about his apparent death Although Jack is normally calm and immovable, he is still capable of feeling real fear if he is vastly overpowered and left in a helpless situation; when Zunisha swung its trunk at him and his fleet in order to repel them, Jack began sweating in fear and watched the massive limb darken the sky above his fleet with his eyes bulging in panic.