First, I'm wondering if the following wording might be a little better, for rules purposes:
Vulnerable - If a card X is vulnerable to another card Y, than any abilities on Y, or on cards played by Y, have "regardless of protection" and "regardless of immunity" when targeting X, and gain "cannot be ignored by X."
I'm not sure how to get rid of the "variable" card references, though that would be necessary to make it a simple, easier-to-understand rule for the game.
For In the Land of Enemies, the current wording wouldn't stop preblock ignore. Not sure if you wanted to try to limit that with this card, too. I'm not sure I like the ability in general, I'd have to give that more thought, but a cleaned up ability would be "Place in an opponent's territory: That player's Heroes are vulnerable to opposing Evil Characters while there are fewer Heroes in battle than Evil Characters. Cannot be negated during the battle phase." Not sure if you could retroactively lose the 'regardless' components though...that could be an issue.