The Phantom Thief is an unnamed Doppelganger and the leader of the three robbers.
He first appears when he kidnaps Tsukune and Moka. He is then seen along side with Kumocchi after Tsukune had woken up and explains to Tsukune what they do. The Phantom sees from the Shikigami that Kurumu, Mizore, Kokoa, Yukari, and Ruby are coming to rescue Tsukune and Moka. He puts on Tsukune's copy to go deal with their friends. Upon reaching the girls, the Phantom was hugged by most of them as he couldn't take it knowing that he had no intrest in girls and is weak against them. Yukari notices the Tsukune that's with them is a fake because he's not wearing the Holy Lock. The Phantom reverts back to his normal self after being discovered. He proceeds to attack the girl's using Kurumu's copy. Kurumu and Mizore tag teamed, but the two were easily beaten. As the Phantom was about to finish off Kurumu, his attack was haulted by Tsukune who proceed to attack. During their fight, Tsukune's ghoul nature got out of hand and the Phantom stopped him by showing his his copy of Kurumu's breasts with the two having nosebleeds. The Phantom comes across Moka and puts on her Inner form's copy and is able to beat all the girls, however, Tsukune placed Moka's Rosario onto his hand to seal away the vampiric powers and with the help from the attack of Kurumu and Mizore's tag team. The Phantom is finished off by Inner Moka's kick and is defeated. The Phantom Thief is arrested and posted in the newspaper articles by the Newspaper Club.
In the Rosario Vampire II chapter 67 Extra II, the phantom thief is shown helping suppress the monster attack on the human populace alongside his cohorts thus indicating that they have released by Tenmei Mikogami to assist in the battle.
Powers and Abilities
Doppelganger Physiology: As a doppelganger, the Phantom Thief is a yokai that duplicates his target's form, appearance, voice, mannerism, and abilities. Doing this allows the thief to be a very formidable foe based on the one that he copies allowing him to turn his opponent's abilities against them. Despite this advantage of having unlimited versatility, his duplicated powers are shown to be at a lesser degree than his target.
- Duplication: The signature ability of the doppelgangers where the thief copies his target's form and abilities for his own use. By taking on the form of an ally he can trick his enemies and by copying a more powerful yokai like the vampire he can be very powerful. Though he in turn copied their weaknesses thus making him as equally vulnerable as his targets. An important fact about his duplication is that he can only copy his target's appearance and abilities as essential artifacts linked to them as Tsukune's holy lock and Moka's rosary cross weren't copied when he took their forms.
- Flight: Upon duplicating Kurumu's form, the thief gained the ability of flight through her succubus wings.
- Enhanced Speed: After copying Kurumu, the thief combined her speed and his own allowing him gained greater speed as he was able to easily dodge all of the attacks the Newspaper Club threw at him. In fact he was able to easily dodge Tsukune's ghoul-enhanced attacks though it was mostly because Tsukune became rather animalistic while in his ghoul mode thus making his movements predictable.
- Enhanced Agility: With Kurumu's form, the thief became very agile to the point of effortlessly dodging all of the Newspaper Club's attacks with acrobatic movements.
- Claws: With Kurumu's form, the thief gained very sharp claws that enhanced his attacks.
- Enhanced Strength: With Inner Moka's form, the thief became a very strong opponent being able to send the members of the Newspaper Club flying away with palm strikes while heavily injuring them.
- Enhanced Durability: With Inner Moka's form he became very durable as he could take even the duet techniques from Kurumu and Mizore that were specifically created for defeating Moka with little damage. In fact the only thing that defeated the thief all together was a powerful kick to the face from the real Inner Moka who being the original was much stronger.
- Great Demonic Aura: Upon copying Moka by taking Inner Moka's form, the thief exerted the same powerful Yoki that Inner Moka releases whenever Tsukune unseals her.
- Enhanced Stamina: The Phantom Thief was capable of exerting himself for a considerable amount of time as he had fought the entire Newspaper Club after using his duplication to copy their powers with little time to recover.
Master Hand-to-Hand Combatant: The thief is shown to be a very powerful martial artist with him combining martial arts he learned with his duplicated powers for greater effect. He was able to fight off most of the Newspaper Club by himself upon copying Kurumu's form and nearly won and defeated all of them when he took Inner Moka's form. He claimed to have mastered every martial arts from humans and that he can use the full power of a stronger body he copied. He is skilled enough in combat to read the level of skills his opponents have such as easily seeing Tsukune as an amateur in combat just after the latter made his first attack after joining the fight.
Expert Strategist and Tactician: The thief proved himself to very crafty as instead of fighting the Newspaper Club straight out he plotted to destroy them while their guard is down instead. This is shown when the thief copied Tsukune's form in order to have the club lower their guard by pretending to be Tsukune with the only hitch to his plan being unable to copy the latter's holy lock. He also takes complete advantage of whatever form of yokai he copied such as Kurumu's well endowed body to anger Kurumu and throw off Tsukune when the latter was about to release his ghoul nature.