Walkthrough for the "Tribes of the East" expansion.

Sorry, I didn't express myself clearly. Here's the last Academy Castle, and I can't capture it. I have a decent-sized army, but could you please tell me how many troops I need to capture the last castle without any problems? And would it be better to attack with an army consisting of magical warriors, or should I use Orcish warriors, or a mixed army? Thank you in advance!