Purple Dementor (퍼플 디멘터, peopuel dimenteo) was an ancient Observer. It was ultimately destroyed by Yuri.
Powers and Abilities
Purple Dementor boasted incredible defensive capabilities, being able to tank Ha Yuri Zahard's strikes without so much as taking a lick of damage (albeit she wasn't using her full power). It was also capable of generating powerful high-density shinsoo blasts from its mouth. However its secret weapon lay in the second finger on the Purple Dementor's right hand and inside it was contained an extremely potent poison that was capable of even making High Rankers temporarily lose consciousness. The poison is only released from the Dementor's fingertip when it so desires.
According to SIU the Purple Dementor is not something Pedro could use under normal circumstances, and only Pedro could use it as he was authorised as the conductor of the train. It actually has a lot of useful abilities for scouting and for battle, yet Pedro was unable to use it to its full potential.