Tag- Nier Replicant Codex Site

Completing the weapon Codex is the only way to achieve in the ver.1.22 remake. Therefore, the "Tag- NieR Replicant codex" strategy is vital: if you haven't tagged (upgraded) every weapon, you cannot access the final, cathartic conclusion of the narrative.

From a gameplay

Weiss isn't just a book. He is the memory of a specific researcher. The Codex hides this fact in plain sight, referencing "Project Gestalt" only in the highest tiers of weapon upgrades. Tag- NieR Replicant codex

Spend an hour in the menu. Upgrade the weapons you never use. Read the stories. The Shadowlord isn't the villain. He is just the last paragraph of a codex entry nobody else bothered to read. Completing the weapon Codex is the only way