Procedurally generate the game-equivalent of Elbereth each game (the literal string “Elbereth” does nothing special anymore), and make it fairly likely to appear somewhere in the Dungeons of Doom.

When a spellbook’s ward is studied, it is possible to get a non-failure, non-success result of “you’re not skilled enough to tell if there is a useful ward here”. This is done by throwing the player’s Int, XL, and possibly other stats into some deterministic function along with the book’s object id and the ward it actually contains.