The Silver Case (event)
The Silver Case is an important event in the backstory of the game of which it is the namesake, The Silver Case, and the world of Kill the Past as a whole. It was the final crime of Format Kamui in 1979, and the truth of what happened in it has distorted considerably over the years; in The Silver Case and its supplemental material, numerous different versions of the case are recounted.
Summary
The only consistent information in all tellings of the Silver Case is that it involved the criminal Kamui Uehara, the TRO/CCO Alliance, and that it took place in 1979. The basic story goes that, as the conflict between the TRO/CCO Alliance and the FSO escalated in what would become Ward 24, Kamui stabbed Ginji Nakane, the chairman of the Alliance, outside the TTV Station building with a metal pipe. Kamui then went to the TV Tower, where the other 10 high-ranking Alliance members were having a secret meeting, and murdered them all. He was then arrested by Regional Investigation Unit Special Agent Tetsugoro Kusabi. Officially speaking, the incident wasn't supposed to go public outside of the name of the arrested, but various aspects of it managed to disseminate themselves into the culture regardless. Accordingly, the various tellings give wildly different dates as to when the event happened, such as March, June 6th, or December 7th. It was also largely suspected that the FSO was responsible for contracting Kamui. The name "Silver Case" supposedly came from the old age of the murdered (i.e. "silver hair" for grey hair).
However, Tetsugoro Kusabi himself has his own different versions of the story. Initially, he claims that he actually killed Kamui on that day; the story that Kamui was arrested was part of a government cover-up that paid off with the use of the Shelter Kids Policy, so the Ward 24 government could pass off future Shelter Kids as the same person as Format Kamui. While this is mostly true, Kusabi later clarifies further, revealing that he didn't actually kill Kamui, as Kamui may have not been a serial killer in the first place. In Kusabi's final explanation, he reveals that the Silver Case was actually named after Kamui's silver eye. The truth of the matter is that the old men of the TRO/CCO Alliance killed both Kamui and eachother over the eye. The victor, the only man left standing, was Uminosuke Hachisuka, who took the silver eye into himself. As the sole witness, Kusabi was declared "the man who arrested Kamui", and made part of the cover story.
Importance
The impact of the Silver Case is less because of the death of Format Kamui or even the TRO/CCO Alliance members. Instead, it was because of the presence of a silver eye in the hands of a member of the Kanto government. The silver eyes are key to Sundance Tribe rituals that can serialize consciousness and personality across different bodies, and Uminosuke Hachisuka had acquired a taste of this power. The Shelter Kids Policy (and the numerous effects that had on everything and everyone in the Ward and beyond) was put in place with the purpose of creating more silver eyes; it also seemingly led to the invasion of Lospass Island that occurred on the same year as the Silver Case. Because of the Shelter Kids Policy, Kamui (along with his artificial counterpart Ayame Shimohira) began proliferating in the Wards, which created all kinds of further developments in not just government operations, but seemingly the future of humanity itself, given the more metaphysical applications of silver eye and Kamui technology.