Guildias is a police detective who arrests Guys and has him charged with murder. He regularly visits, tortures, and rapes Guys in the prison.

As the game progresses, Guildias is gradually revealed to suffer from a number of delusions, not to mention being an outright pedophile who framed Guys for murder because of unnecessary fear that Guys witnessed him with a boy in town named Myuca.

Guildias locked Myuca in a room and forced him to dress as a girl to settle possible suspicion when the two were out in public. At first, Guildias' intention for kidnapping the boy is never directly stated, but through the man's various delirious states, it becomes obvious Guildias was very much in love with Myuca and had a sexual relationship with him. Because he is prone to delirium, Guildias suspected Guys either witnessed him with Myuca, or had direct plans to help free the boy from his imprisonment. In a fit of rage, Guildias accidentally strangled Myuca to death. Later on, he also murdered a man named Jared, who was a private investigator hired by Myuca's family and was already suspicious of Guildias for the kidnapping. To clear his name, Guildias framed Guys for the murder of Jared.

Guildias visits Guys a number of time in prison, simply to abuse him and seemingly to cast over his pain and regret of murdering Myuca. During these visits, Guys begins to witness Guildias' unstable personality, especially when it comes to the idea of Guys possibly being released from prison. To prevent this, Guildias threatens Guys' friends, who were supposed to give witness statements to exonerate the boy during his first retrial. Later on, when realizing Lusca may have even more evidence to prove Guys' innocence, Guildias attempts to murder Lusca by shooting him. He also eventually visits Guys for a final time to torture and humiliate the boy as a way to force him to give up on another retrial.

Despite his efforts, when Guys is granted a second retrial, Guildias loses his sanity in the courtroom and is escorted out by guards. His fate is debatable, as it is never stated in the game, but in the OVA, he commits suicide. In the bad endings where Guys does not live to prove his innocence, Guildias' is never mentioned, therefore he may or may not have eventually lost his sanity in those scenarios.