Sekiro uses one profile-level S0000.sl2 file, so a file replacement can roll back several in-game slots at once. The safest routine is therefore simple but strict: close the game, copy the whole account-ID directory, keep more than one dated generation, and only then experiment. Steam Cloud is another revision source; if a manual restore appears to revert itself, solve the synchronization conflict before overwriting the folder again.
Identify the exact save you intend to edit
The researched Sekiro: Shadows Die Twice PC save location is Windows: %APPDATA%Sekiro<user-id>S0000.sl2 | Linux / Steam Play: Steam Play: <SteamLibrary-folder>/steamapps/compatdata/814380/pfx/. Known file/folder pattern: S0000.sl2. Storefront context: Steam. The user-ID directory is part of the save context. Do not assume a copied S0000.sl2 belongs to the active Steam identity. Do not edit a similarly named file from a different profile, edition, or cloud cache.
Make an untouched backup first
Copy the entire Sekiro account-ID folder with the game closed. Keep multiple dated versions because the game continually updates the same container. Keep that copy outside the live save directory and do not overwrite it with later experiments. Cloud context: Steam Cloud is documented. If a launcher can synchronize the save, prevent it from silently replacing either the original or edited copy while testing.
Understand the format boundary
The Steam PC profile is a single S0000.sl2 container under an account-ID directory. Multiple in-game slots are not separate operating-system files. File-extension context: .sl2 Compatibility note: One .sl2 container can hold multiple in-game slots. File-level replacement rolls back the profile container, not one isolated character slot. These facts help identify the save but do not automatically reveal every field, checksum, encryption rule, or version-specific structure inside it.
Use only a Tool whose claim matches the file
Generic viewers and diff tools can inspect bytes without claiming game-specific semantics. A game-specific editor should be used only when its Tool page explicitly lists Sekiro: Shadows Die Twice, a matching supported version/container, and a Verified operational runtime. A planned URL or Game Hub is not evidence that an editor exists.
Test the edited copy safely
Write to a new output file when the Tool supports it, keep the original backup, restore the edited copy into the correct profile/storefront location, and launch the game only after the file operation finishes. If the game rejects it, If a restore is replaced on launch, compare Steam Cloud state and modification times. Keep the original local file before testing any imported container. Return to the untouched backup before trying another change.
Verification context: Windows path, S0000.sl2 filename, Steam Play behavior, and Steam Cloud support were reviewed against current PCGamingWiki coverage.