There's a trick with the Tower. If you don't teach the Earth Magic expert skill, when casting Antimagic on any monster, the Djinn will cast a spell of level 3 or higher.
So, if you cast Antimagic on, for example, mages, and then have the Djinn cast a spell on a Naga, will the Djinn cast a spell of level 3 or higher on them? Or, if the Djinn casts on the same mages, will it be level 3 or higher? If it's the second option, that's understandable. If it's the first, it's an interesting trick, but how accurately has this been verified?