Tooru Sayonaki

Tooru Sayonaki (real name: Vlad Dracula) is the main antagonist of the first three volumes of the light novel series Aria the Scarlet Ammo, and the main antagonist of the anime. Introduced as a teacher in Tokyo Butei High, he is in reality a centuries-old vampire, a high-ranking member of I-U, and the archenemy of Riko Mine Lupin IV, being the one who imprisoned her in a cell and experimented on her, as well as stealing her late mother's rosary.

He is voiced by Kenji Nojima in the Japanese version of the anime and J. Micheal Tatum in the English version.

About
Sayonaki is initially introduced as a part-time instructor at Tokyo Butei High. His lectures involve the Medica Division, which specialises in rescue operations and medical science. It's likely that his knowledge of the subject comes from his frequent experimenting. When Kinji and Aria first arrive at Vlad Dracula's mansion, he initially poses as the caretaker of the mansion, but is in fact Vlad Dracula himself. He is the one who took Riko out of prison and later experimented on her to make her a better specimen for the Lupin family. In the past, he also had an encounter with twin sisters who were ancestors of Jeanne D'Arc XXX.

Sayonaki regards himself and Vlad to be two separate beings, describing the latter as a being he's destined to never meet. This is due to the fact that Sayonaki is a form he took on via assimilation of human blood. In his vampire form, Vlad is practically immune to any kind of damage, with the exception of four weak points. Only if one shoots all of these in quick succession can he be defeated.

Despite his great power, Vlad is also an extremely petty being who seems to go out of his way to spite Riko; he stole her late mother's rosary, the only thing Riko has to remember her by, purely because he knew how much it means to her and reveals to Aria and Kinji that she's like Aria (i.e. she inherited none of her ancestor's trademark abilities) purely out of sadism. Part of this is due to the fact that abusing someone is necessary for his Vlad person to activate, but given his utter lack of empathy towards his actions, it is clear that he enjoys them too.