It sounds like you're referencing a "Steins;Gate Codex Exclusive — Deep Piece."

Let me break down what this likely refers to, as there isn't a single officially titled "Deep Piece" in the Steins;Gate visual novel or anime.

This appears to be a fan-made or archival deep-dive analysis piece—likely a long-form video, article, or podcast episode—that was published as an exclusive to a collector's community (like a "Codex" group, similar to a Patreon or private forum).

Here’s what such a piece typically contains when fans discuss "deep" Steins;Gate lore:

The Three Major Revelations

  1. Kurisu’s Scar: The Codex Exclusive confirms that Kurisu retains faint memories of her death in the Beta line, manifesting as a recurring nightmare she calls the "White Lab Coat Paradox." This explains her subtle anxiety around Okabe in the original ending.
  2. Suzuha’s Fate: A hidden audio log reveals that the Suzuha who left for 1975 to obtain the IBN 5100 did not just vanish—she succeeded in a different world line, creating a branch where she lives to be 80 years old, watching over the lab from the shadows.
  3. The True Divergence: The number 1.048596% is a lie. The Codex updates the meter to "1.048596% Ω (Omega)." Omega signifies a closed loop. The document posits that reaching the true "Free Line" requires a divergence of 1.486110%—a number later confirmed in the sequel, Steins;Gate 0, but never capitalized upon until now.

CHAPTER V: THE CODEX RECOMMENDATION (The True End)

To experience Steins;Gate as the Codex intends, you must reject the passivity of watching.

  1. Play the Visual Novel (Steins;Gate Elite or Original): The anime is a masterpiece. The VN is the Bible. The branching choices (triggered by the phone’s ringtone, not dialogue options) are the true mechanic of madness.
  2. Watch Steins;Gate 0: It is not a sequel. It is the required prequel to the original’s ending. It shows the 15-year hell Okabe endured to write the video D-Mail that saves Kurisu.
  3. The Movie (Deja Vu) is Apocrypha: Beautiful, but it breaks the established physics (Reading Steiner affecting the past without a shift). Enjoy it as a dream.

The Narrative Bomb: What the Codex Reveals

Most fans believe the true ending of Steins;Gate (the "Steins Gate" world line) is a utopia where Kurisu and Mayuri both live, and World War III is averted. The Codex Exclusive shatters this comfortable illusion. It reveals that the Steins Gate world line (Divergence Number 1.048596%) is not static—it is actively decaying.

Through the "Lost Divergence Logs," we learn that Okabe’s Reading Steiner is not a blessing but a physical scar on the universe. Every time he leaps between world lines, he leaves behind a "quantum echo"—a ghost of a memory. The Codex Exclusive reveals that six of these echoes have become self-aware, forming a secondary antagonist: The Unobserved Observers.

The exclusive chapter, "Epigraph of the Closed Loop," forces the player to control a new protagonist—a SERN agent who has hacked into a microwave phone-microwave (the PhoneWave) from a world line where Okabe failed. This "reverse perspective" is the crown jewel of the Codex. It shows that for Okabe to reach Steins Gate, he inadvertently created a prison loop for thousands of other consciousnesses.

1. The Attractor Field Convergence

Certain events are “fixed points.” In the Alpha Attractor Field, Mayuri Shiina (Lab Mem 002) will die on August 13th, regardless of how you save her. Train? Heart attack? Molotov cocktail? The universe will conspire to correct the anomaly. Codex Ruling: Convergent events are not fate. They are logical gravity. Remove one cause, another appears.