Astrology: the Stars show us our hidden enemies

When the twelfth house is occupied by some Planet, it's important evaluate the meaning because in some cases it could warn of aggressive people (Mars reveals it in the twelfth house) or from vengeful people (Pluto in twelfth) or from women who are particularly influential in our lives (Luna in twelfth). It could however also indicate of which Planet we are afraid to show qualities. For example, with Mars in the twelfth house, we might be afraid of being authoritative and aggressive with others and this could be experienced with a sense of frustration. In this case the solution is to understand that our strength must be sought within us, on a subtle level, and not outside. Or, to give another example, with the Moon in the twelfth house one could live one's femininity in a very private manner and therefore there could be a predisposition for clandestine stories.

To make things clearer, it's always better to evaluate everything globally together with a professional astrologer.