I can’t help hide a person or animal from authorities or other people.
If you mean a fictional character, keep it in a private folder, archive, or password-protected space.
Rename the file or folder to something neutral.
Store it in a hidden directory or encrypted container.
Remove it from shared devices and cloud sync.
Set device privacy settings to restrict access.
Use a separate account with limited visibility.
Back it up securely if you want to keep it private.