The Neko Neko no Mi, Model: Saber Tiger is an Ancient Zoan-type Devil Fruit that allows the user to transform into a hybrid and full version of a saber-toothed tiger at will. It was eaten by Who's-Who.
Sāberutaigā (サーベルタイガー,Sāberutaigā?) is a Japanese way of referring to the saber-toothed tiger, loaned from the English "Saber Tiger" (though the latter is not used in English).
Strengths and Weaknesses
A user of this fruit's power can turn into a "saber-toothed tiger" or Smilodon—a powerful, predatory big cat from prehistory that is characterized by its elongated, curved fangs on its upper jaw. The ability's current user Who's-Who, who is an already large man, grows to a very notable size in his full Beast Form, dwarfing his human-sized subordinates and a 3m-tall fish-man. The Human-Beast Form, likewise, is considerably large in terms of height and muscle bulk.
As with other Ancient Zoans, this fruit's transformation bestows greater strength and durability than regular Zoans'. The user gains a pair of long, sharp canine fangs usable for biting attacks, as well as retractable claws on their hands and feet, much like other feline Zoan powers. Amongst the Ancient Zoans, it possesses quite high agility despite the user's enlarged size.
Because Who's-Who gains a tail in this form, opponents may exploit this by stepping on it, preventing Who's Who from escaping their reach and forcing him into a precarious position for subsequent moves. Aside from that, no weaknesses of the fruit's power are known besides the standard Devil Fruit weaknesses.
Who's-Who was first shown in his full Beast Form relaxing at the "Nekoka-fé" in Kaidou's fortress. In combat, Who's-Who seemingly uses his sharp canines to bite foes with.
Being a former CP9 agent and master of Rokushiki, Who's-Who is able to combine his superhuman martial arts prowess with the physical strength boost and animalistic features granted by his transformation, especially of his Human-Beast Form, greatly enhancing his general combat skills much like other Zoan-using members of CP9 (like Rob Lucci or Kaku). Jinbe, who is an expert martial artist and familar with Rokushiki, admitted that he had never witnessed anything remotely similar to Who's-Who's techniques.
Gagan (牙銃,Gagan?, literally meaning "Fang Gun"): A technique that employs the use of Tobu Shigan in conjunction with Who's-Who's Human-Beast Form. Who's-Who quickly thrusts his maw forward, releasing a blast of compressed air that is shaped like his fangs. The blast makes a biting motion once it connects to a surface, gouging a clean, round hole out of the struck target. The attack was first used against Jinbe, who successfully dodged it. Later on, it was shown to be strong enough to pierce through Jinbe's Busoshoku Haki. In the VIZ translation, the attack is called Fang Pistol.
Tekkai "Kibasen" (鉄塊「牙閃」,Tekkai "Kibasen"?, literally meaning "Iron Mass: 'Fang Flash'"): A technique that employs the use of Tekkai in conjunction with Who's-Who's Human-Beast Form. Who's-Who crouches into a pouncing position, hardens his teeth and then leaps towards the target face-first at high speeds, attempting to tear them with his fangs. It was first used against Jinbe. While the attack was able to push Jinbe a reasonable distance, the fish-man was able to ultimately block and counter it with his own Busoshoku Haki and Fish-Man Jujutsu. In the VIZ translation, this attack is called Fang Flash.
Shigan "Madara" (「指銃」斑,Shigan "Madara"?, literally meaning "Finger Gun: 'Speckles'"): A technique that employs the use of Shigan in conjunction with Who's-Who's Human-Beast Form. Who's-Who jabs the index fingers of both his hands toward his opponent in extremely rapid succession in order to stab the opponent's body numerous times, with his claws serving to increase the damage potential. It was first used against Jinbe, being effective at first, though was eventually stopped and countered by the fish-man's Busoshoku Haki, which overwhelmed Who's-Who's own. In the VIZ translation, this attack is called Finger Pistol Spots. The kanji for 斑 also translates to "unevenness/inconsistency" if read as mura.
The saber-toothed tiger (correctly named Smilodon) constitutes the best-known genus of saber-toothed cats and is, overall, one of the most famous prehistoric mammals. Despite its popular name, it is not closely related to the modern tiger or, for that matter, any extant feline.
It is theorized that the Smilodon actually possessed a short, stubby tail, unlike modern large cats as well as Who's-Who's transformation, which respectively bear long tails.
Smilodon have been artistically restored with plain coats (like Who's-Who's) as well as spotted ones (seemingly the ancestral condition for feliforms), both of which are considered plausible.
Befitting his Devil Fruit ability, Who's-Who's closest subordinates appear to follow a cat theme, including several feline SMILE users.
While Who's-Who uses his elongated canine fangs as a weapon, the real animal only used its maxillary canines to deal quick finishing blows after subduing its prey with its strong forelimbs and claws, by swiftly severing arteries in the neck and throat area (as opposed to the slow, suffocating bites seen from modern cats). The fangs of a Smilodon were actually brittle and could easily break if used in a fight.
While in his beast-form, Who's-Who grows several times larger than ordinary humans, as well as regular sized saber-toothed tigers.