Age: 27 (start of game)
Date of Birth: February 1, 1984 (Aquarius)
Height: 176 cm
Weight: 63 kg
Blood type: A

A cheerful and jovial detective, Adachi often serves as the story's comic relief. He jokingly refers to himself as the 'slave' of Dojima, complaining of the workload that his partner piles on him. Adachi also often accidentally blurts out the police investigation results to the Investigation Team, much to his own chagrin. He can be seen hanging around Junes Department Store, usually planning to buy cabbages to cook for dinner.

A young police officer in Inaba's police department, and Dojima's partner. In the Normal/True ending path it is revealed that Adachi is behind the two initial murders. He became interested in Mayumi Yamano and Saki Konishi and pushed them into TVs when they spurned his feelings.

Believing Mayumi Yamano to be his soulmate, he confronted about her affair with Namatame. When she rejected his advances, he planned to hold her against the TV to scare her, but to Adachi's surprise, ended up falling in completely. He made similar advances on Saki Konishi, but was rejected again, and out of anger, threw her into the TV.

Afterward, he tricks Namatame into kidnapping people under the idea that he was keeping them from danger. He explains that his reason for doing so is nothing more than to entertain himself and disgust for the human world, in fact, he reveals that the only reason he became a police officer was so that he could legally carry a gun.

He gained his power from Izanami like the Protagonist, though he seems to be unaware of Izanami's influence. He was defeated by the party and arrested for his crimes.

If the player continues towards the true ending the protagonist receives a letter from a recently convicted Adachi, stating his suspicions of a true Conductor behind all of the events of the midnight channel, providing the investigation team with new insight to their reasoning.

It is heavily implied that he is suffering so much because of the expections and pressure from society he has to deal with.