Ptilol

プチロル

Ptilol (known as Petite Roll in the manga and Petirol in the dub) and Cyprine are jointly regarded as the fifth member of the Witches 5. Naoko Takeuchi stated in the Materials Collection that Ptilol is merely an extension of Cyprine's power, yet they appear to act as a single entity. Ptilol takes its name from the mineral ptilolite.
Ptilol is simply the other half of the witch Cyprine.
In the anime, Cyprine is depicted as the final member of the Witches 5. She reveals her "other self," Ptilol, only when confronted. The pair proves nearly invincible to the Sailor Senshi, as one consistently blocks incoming attacks with her powers while the other fires blasts from behind. Gradually, the Senshi manage to trick the two into blasting each other, killing both simultaneously.
In the manga, Cyprine is the highest-ranking witch at level 999, and her death attack is "Ribbon Buster." Kaolinite specifically summons her to deal with the Sailor Senshi. Cyprine attacks Haruka Tenoh in her apartment. Haruka promptly transforms into Sailor Uranus, and the Inner Senshi, Sailor Neptune and Sailor Pluto, appear to assist their fellow senshi. Cyprine then uses her power to amplify the preexisting feelings of hostility and tension between the Inner Senshi and Outer Senshi. Horrified by this maneuver, Sailor Moon attempts to destroy Cyprine with her Moon Spiral Heart Attack, but the attack fails. Cyprine remains unhurt and instead splits herself into two halves: herself and another, Ptilol. These two are only one person divided in two, not twins. Cyprine is the sole fifth witch, and Ptilol is merely an extension of Cyprine that has manifested as Ptilol. Cyprine and Ptilol are one, and they believe that no one can defeat them. Sailor Moon gathers energy from all the senshi to create the Holy Grail, using it to transform into Super Sailor Moon. She then uses her "Rainbow Moon Heart Ache" attack to destroy Cyprine and Ptilol.