Clyde's Fortress is located in Clyde's backyard. It is the base of his Army of Darkness.
The fortress is a giant tower built around a large tree. There is a moat around it and a gate blocking access to the tower. There are multiple levels of the tower, ending with a throne room at the top. To the left of this room is a shop and a balcony.
There is a conveniently placed shop before the final boss battle at the top of the tower just before the high balcony. It sells every type of food items in all sizes, as well as some patches and strap-ons. A Clyde wig can also be bought.