Summoned Berserker axes can be augmented with an upgrade item and any axes of the same type summoned post-hence will be added to the stack, complete with the augmented effect. The effect will remain on the axe stack forever so long as not all of them are thrown.
At the start of the game, if you choose to be on the evil side you'll end up at the city of Drundar. You'll need to find eight locks to access the arena where some bosses reside. There's a glitch that allows you to double the amount of locks you have found. Firstly you unlock some of the locks then save, and exit the game. When you next load your game you will have double the amount of locks on the lock counter than you previously had. Unlocking the rest of the locks will not affect your game (even though it will say you have unlocked more than 8 locks). This can only be done once.