My fortress has recently captured an ettin, and I would like to turn him into an unstoppable killing machine whom I want to use to dispose of captured goblins and other non-tameable creatures.
The ettin, as any other intelligent creature, can have his combat skills trained. I don't know yet if I can make him equip weapons and armor, but I have nothing against letting him use only unarmed attacks.
What would be the most efficient setup allowing me to train the ettin's combat skills? When answering, bear in mind that the ettin is hostile and can destroy buildings.