Age: 18
Birthday: April 30
Height: 172 cm (5'8")
Weight: 58 kg (127 lbs)
Blood type: A
Occupation: 7th Member of Mekakushi-dan
Songs: Lost Time Memory, Transparent Answer (Toumei Answer)
Eye ability: Retaining Eyes
The main protagonist of the manga and brother of Momo Kisaragi, Shintarou is a hikikomori and as such, he has a hard time dealing with people. He seems to be constantly bothered by Ene.

First appeared in Jinzou Enemy. A hikikomori (recluse/shut-in) young man with an IQ of 168. In middle school and high school, before he was a hikikomori, he performed at the top of his class in National Mock Examinations. He is no longer in school. After dropping out, a mysterious software enters into his computer named "Ene," and, being unable to control her actions, his lifestyle is at a loss. Due to one of Ene's pranks, his computer breaks down, so both Ene and him go to the department store for shopping where they happen upon a group of terrorists. They end up stopping them together with the Mekakushi-dan. After this, he and Ene come to join the Mekakushi-dan.

Ayano sat behind him in class. He once saw her crying in the classroom while no one was there to watch, and realized that this was probably her true self, but he didn't call out to her. Later, Ayano committed suicide and he blamed himself for it because he didn't call out to her even though she had helped him in so many subtle ways. Because of this, he believes he deserves to rot away and becomes a hikikomori.
He did not have an eye power in the original timeline. Sometime later, he wished to remember the tragedy and Mary gave him the Retaining Eyes snake, allowing him to remember everything that has happened in every timeline that had passed so far. However, this power would not activate unless something triggered it.
Coincidentally, the Retaining Eyes snake would play a large role in guiding the group to the true ending. During the true timeline, the Retaining Eyes snake took the form of Ayano and tried to trigger its power. Once successful, it allowed him to remember everything and guided him to go into the Heat Haze and save Ayano. Saving Ayano, they leave and confront the Snake of Clearing Eyes.
(Source: Vocaloid Wikia)