A little late, but your topic stayed on my mind.I was reflecting on weapons and my chart, but I just don’t know how to answer that, other that losing is often by self undoing (Saturn in 12). I’d rather spend this time thinking about the last question. Beautiful.
How is it that our open opponents r also partners,and our biggest,the most dangerous enemy is ourself?
I honestly don't know where to start on your question. I think that's why I like it so much.
My guess is that what we face goes away. The 12th represents the buried, the unconscious, the repressed. There are parts of ourselves in the 7th that we disown, but we are kind of conscious about this. We attract people that will light up that part of the chart, and we'll let them play those parts or we'll integrate them.
I think that they are "open enemies" when one completely disowns the energy in the 7th.
Things get complicated in the 12th. My guess is that whatever planets are in this house are very hard, if not impossible to fully integrate. The 12th just spells "lack of...", love(venus), nurturing (moon), structure (saturn) and so on.
And we need these energies to function at our best. I think that the interpretation of "hidden enemies" is one dimensional. It could be also "greatest friend", as in a spiritual teacher, guru - depending on the level of spiritual awareness of the two people involved.
There are also two proverbs that I want to mention. "Keep your friends close and your enemies closer" and "know thyself". I'll ramble about these in another post