Mercury in 12th house in Astrology is a bad position for Mercury. However, it can make one of the best sci-fi or fantasy authors; these people also have a physic vision. However, if Mercury is with Ketu in this house, it can make a person gay or bi-sexual. Mercury and Ketu combo in any house give those tendencies to the native, whether male or female. Mercury in the 12th house in Vedic Astrology also gives a dull mind unless sitting with Venus or Jupiter.
The12th HouseHouse of mystery, your hidden talent, your hidden magic, foreign country settlement, losses but, not necessarily loss of money, it could be loss of enemies or health, as in, you’ll lose enemies, which stands for: you may not have many enemies, or you may not have too many diseases in your possession. If you look at this house carefully, 12th house, which is known as the house of losses or expenditure, can also work to your advantage. We’ll talk about this later. But, 12th house is a major player in fictional writers' careers, as mercury in12th house takes you into a different dreamland, and dimension which is required for a fantasy writer.
The 12th house represents the final stage of life and the inevitable death that concludes it. Any kind of loss or expenditure is signified by the 12th. Positive applications include investments, donations, and getting rid of unwanted things. Negative applications are death, losses, unexpected expenses, theft. The 12th house represents the last portion of the legs, the feet. The 12th house corresponds to Pisces. Jupiter adds a spiritual value to the 12th, and the loss of bondage to the relative aspect of life is indicated: enlightenment or in Sanskrit "Moksha".
Mercury in 12th house person is intelligent because in order for anyone to have good communication, one needs to be intelligent. Mercury is also our
business and management skills due to his calculative and logical nature, and love for the marketplace.
Mercury in Vedic Astrology represents speech. It also governs the logical and intellectual side of the mind, the thinking process that precedes speech and the ability to communicate, and anything related to language, use of symbols, logic, information processing, and connecting with people or things. The influences on Mercury in the chart will determine the clarity of one's intellect and speech and the ability to communicate.
Note: The degree of auspiciousness and inauspiciousness will depend upon a complete analysis of the horoscope (birth-chart).