Who's Who is one of the Tobiroppo, the strongest six Shinuchi of the Beasts Pirates. Prior to joining Kaido's crew, he was the captain of his own crew. Due to his actions and role, he is a supporting antagonist in the Wano Country Arc. Who's Who is a very tall man at over 3.3 meters, lean yet well-toned with particularly long legs and a light complexion. A large mane of wavy, pale-pink hair goes down his back a little past his waist. A chain smoker, Who's Who is always seen with a cigarette in his mouth. Like some of his subordinates, Who's Who wears a mask over the top half of his head down over his nose (where it comes to a slightly raised edge and point), colored red and bearing two long, upward-curving horns, connected to the sides of the mask by circular bases. While his lower face remains bare, including his full-lipped mouth and defined jaw, his ears (on each of which is one still-visible, golden hoop earring) and eyes are obscured, the latter covered with large, yellow circles that do not seem to obstruct the man's vision. For his upper body, Who's Who dons a plain dark, button-cuffed jacket (paired with dark gloves) over a white shirt with a double-winged collar, both unbuttoned to show off his chest and abdominals. The former is tattooed with two swirl-ended lines topping a stylized, thick-lashed eye motif, with his name below spelled "WHO WHO", all in dark color. His lower wear consists of matchingly dark, slim-fitted pants held up by a wide belt with a big and round, stud-lined buckle, and lastly dark dress shoes with single latchets buckled on each side. Who's Who generally maintains a calm and serious disposition, unlike some of his peers who seem prone to bickering or teasing. He does, however, get annoyed easily by noisy people.
An ambitious man, Who's Who strives to become one of the Beasts Pirates' All-Stars by taking a spot from one of the current three, leading him to completely disregard their senior authority; this desire, according to King, springs from Who's Who's past as a captain of his own crew. In accordance, he has also shown himself to be confident in his strength, believing it to suffice for him to kill an All-Star, and even smirking excitedly at the thought of gaining an opportunity to try. Due to his goal of claiming a spot among the All-Stars, Who's Who (like Sasaki) refuses to answer to the current ones, viewing them first and foremost as obstacles to said aspiration and justifying his insolence toward them through their crew's unfixed hierarchy system. His disregard for their seniority is further denoted by how, unlike the majority of his crewmates, Who's Who refers to Queen and King without any honorific, with Queen in particular being an All-Star whose death Who's Who has contemplated aloud. Yet, in spite of his dislike of Queen, Who's Who has shown willingness to set aside their differences in order to deal with internal threats together with his superior, namely by ambushing the perfidious X Drake (suggesting that the aforesaid mention of Queen's death may have been a mere ruse meant to prevent Drake from expecting said ambush). Who's Who is at least friendly enough with the other Tobiroppo to make casual small talk with them. Because, however, some of the other five share his rank-climbing ambition, he views them as rivals, most expressly Sasaki, stating how he wished to find Yamato as fast as possible to preempt Sasaki from doing so first. Ulti and Page One on the other hand are viewed as brats by Who's Who, with him calling their squabbling annoying. Who's Who was at some point made aware of X Drake's status as a traitor and thus aimed to kill him. Instead of tackling him head-on, he was smart enough to trick Drake into an ambush organized by him and Queen. As one of the Tobiroppo, Who's Who holds great authority in the Beasts Pirates, with only Kaido himself and the All-Stars ranking above him. As an ex-pirate captain, he used to have command over his own crew at some point before joining Kaido. Combat-wise, Who's Who is assumed to be very powerful as one of the strongest six Shinuchi, potentially enough to challenge an All-Star for their position, which he appears confident in his ability to do.Who's Who can be quite strategic, leading his then-fellow Tobiroppo Drake into an ambush by using his own supposed feud with Queen as a pretext to convince the SWORD captain into following him.
Who's Who ate the Neko Neko no Mi, Model: Saber Tiger, an Ancient Zoan-type Devil Fruit that allows him to transform into a saber-toothed tiger (and human hybrid thereof) at will. Who's Who is notably large in his full-beast form, dwarfing normal humans. Who's Who carries with him a long katana with a light-colored tsuka, quatrefoil-shaped tsuba, and dark-colored saya patterned with light, multi-petaled flower motifs. His level of skill in wielding said weapon remains to be seen. At some point before the latest Fire Festival, Who's Who was made aware of X Drake's possible treachery (due to the latter freeing Trafalgar Law from imprisonment) and thus conspired with Queen to lead Drake into an ambush. Sometime after the Fire Festival had commenced, the Tobiroppo, including Who's Who, arrived on Onigashima. Kaido was supposedly the one who had them brought to his fortress, where they waited for him. Ulti expressed her desire for Queen to die, and Who's Who wondered which of the six would take his spot if that happened. When this discussion caused Ulti and Page One to start arguing, Who's Who told them to be quiet. Ulti then insulted Kaido as they awaited the meeting, causing the other Tobiroppo to rebuke her. After Kaido then greeted the six in his castle, Who's Who was perplexed to learn that King was the one who had summoned them, with King bringing up Who's Who and Sasaki's ambition to become All-Stars and telling them to know their place. Kaido then gave the Tobiroppo the mission of finding his "son" Yamato, saying he would let them battle one of the All-Stars for their position if they succeeded, terms that Who's Who eagerly accepted. Later, Who's Who gathered his men and told them to ignore the commotion caused by Monkey D. Luffy, Roronoa Zoro, and Eustass Kid invading Onigashima, to instead focus their efforts on finding Yamato. He was later notified that Luffy and Yamato had gone to the Performance Stage in front of Kaido's castle. After the Ninja-Pirate-Mink-Samurai Alliance had fully begun waging war inside the Skull Dome, Who's Who received a call from King informing the Tobiroppo that the challenge for an opportunity to fight the All-Stars was cancelled, and that they were to stop the enemy alliance from getting to the roof of the dome. Who's Who then approached Drake in a castle room and urged him to join him in killing Queen. However, this was a setup for Who's Who and Queen to instead launch their planned ambush on Drake. As they accused him of treachery and questioned him, a sudden explosion occurred, enabling Drake to flee the castle to the Performance Stage. Some time later, Who's Who received another call from King, who ordered the Tobiroppo to find Kozuki Oden's son, Momonosuke, and kill him in order to break the enemy samurais' will to fight. Consequently, Who's Who and his subordinates camped out at the Nekoka-fé on the fourth floor of Kaido's castle, with Luffy and Jinbe eventually reaching said floor. Whereas Luffy went further up toward the Skull Dome's roof, Jinbe remained on the floor, defeating several of Who's Who's subordinates until coming face-to-face with the Tobiroppo, now as a fully transformed saber-toothed tiger. Who's Who complained about Luffy getting away and Jinbe beating up his men, before revealing that he had seen the former Warlord in the past. Jinbe noted how he might recognize Who's Who if he took off his mask, but the Tobiroppo stated it would not happen.
