Can I give up on a den that's being attacked by Templars?

Solution 1:

They'll wait for you to get there. I'm not sure if there are any consequences if you go forever without even visiting that den, but it doesn't seem like there will be...I can confirm that they'll wait at least several hours.

If you fail a den defense, the only consequence is that the den reverts to Templar control, and you have to kill the captain all over again - it's like you never had it in the first place.

Solution 2:

The den will remain contested until you choose to defend it. Should you fail Den Defense, you can always capture it back. However, your apprentices gain experience from successfully defending a den.

Solution 3:

I haven't played the game personally, but I do remember seeing a quote about this very topic in the IGN review of the game.

Frequently the game throws overwhelming odds against you, making the entire affair an irritating, extraneous mess. Even more irritating - if you lose, you can immediately climb a wall and assassinate the enemy leader again, rendering your previous 10-minute chore almost pointless.

Solution 4:

Let the den go if you don't want to defend it. Capturing it back is so much easier than defending it.