Vedic Wisdom gives us a caricature of the nature of the 6th lord in the 12th house as creating a person who does not observe non-violence, but winds up harming other beings. I will now explore the reasoning for this caricature.
Harming beings: This specifically refers to the Vedic principle of ahimsa (non-violence), which is one of the very primary virtues. Ahimsa is a topic of the 12th house. The 12th house is the sky above the eastern horizon. The eastern horizon is where the Sun rises, and therefore represents birth and becoming visible and physical. So the 1st house, the eastern horizon represents the physical self. The 12th house is the sky above this. In the sky just above the horizon is all the wind and rain which erodes and dissolves the land. Thus the 12th house represents everything that erodes the physical-centrered and self-centered way of existing.
In a self-centered way of existing, we naturally feel like we are important and the people and things in the world are resources for us. The 12th house wants to enlighten us by eroding this self-centered illusion. But if the 6th lord – lord of obstacles – inhabits the 12th house, the symbolism is that there is a blockage, an obstacle inhibiting the 12th house from doing so. If we are in a self-centered concept of life, we exploit others. We do not take care to be non-harming (ahimsa). This is what the author is alerting you to. He is telling you that you must pay much more careful attention to being non-harmful to others. Why live in a way that leaves a big footprint behind you? Why live in a way that inconveniences others? Why for example, eat meat? It is not at all necessary – although maybe someone might think it is “enjoyable.” These sort of debates have to be welcomed more hospitably into the heart of us with 6th lord in the 12th house, or else we risk seriously damaging our future karma and having our next birth in very unfavorable conditions.
– Vic DiCara