Doubt Doubt (疑わしきは罰せよ（ダウトダウト）) is the Servamp of Envy. He is always seen wearing a long black coat and hides his face with a paper bag. His Eve is Mikuni Alicein, who calls him Jeje.

Not much is known about his background, he is the third oldest of the Servamps.

He seemed to be alone for a long time until All of Love invited him to the Alicein's. There he used to live in the cellar of the mansion and didn't show himself.

Mikuni's mother formed a contract with him and kept him until Mikuni formed a new contract. He gave him the name Jeje and used him to kill his mother. After that incident, Doubt Doubt left the mansion together with Mikuni.

He followed his Eve and together with him, he joined C3 and the two of them teamed up with Tsurugi Kamiya. He and Tsurugi seemed to talk every night.

Later he and his Eve left C3 again and went their own path.

Jeje is very calm and quiet—he nearly never talks—and if he does he mostly mumbles. He likes to built ships in a bottle and likes being on his own. He hates it when Mikuni promises him his blood and then breaks his promise, and even knowing Mikuni always says "no" if Jeje wants his blood—Jeje falls for it, believing his Eve and hoping to get some.

(Source: Servamp Wikia)