Installed D7 with Minimal profile and root user do not have any role set to it. How to create a locked role for root? Now I can create only simple role which can be easily edited and deleted. I need a role for root user (user ID 1) for some other modules that requires selecting a role.

Now installing minimal profile of Drupal my root user is roleless. Don't know how to call it.

In overall I need something that the root user would be undeletable/uneditable by any other admin who has power to edit users and permissions and roles.
Navigate to /admin/config/people/accounts#edit-admin-role and select from the list which role should be treated as "Admin role".