The 6th, 8th, and 12th houses are known as the Dusthana houses, which are associatedi with challenges, losses, and adversities. When the lord of one of these houses becomes retrograde, its effects can be intensified, leading to complex and often unpredictable outcomes. A retrograde planet is said to be re-evaluating or revisiting the themes of the house it rules.
6th House Lord Retrograde
The 6th house rules over themes like debts, diseases, enemies, and daily conflicts. A retrograde 6th house lord may bring back past health issues, old debts, or unresolved legal matters. It can also indicate that a person might have to deal with recurring conflicts or enemies from their past. The retrograde motion suggests a need to re-examine and resolve these issues.
8th House Lord Retrograde
The 8th house is the house of transformation, sudden events, longevity, and hidden knowledge. When the 8th lord is retrograde, it can amplify the transformative energy of this house. It may cause a native to revisit or re-experience significant life changes, such as unexpected inheritances, accidents, or deep psychological shifts. It can also suggest a deep-seated desire to explore occult or esoteric knowledge.
12th House Lord Retrograde
The 12th house is associated with losses, foreign lands, isolation, and spiritual liberation. A retrograde 12th house lord may cause a person to revisit past losses or deal with issues of isolation and confinement. It can also suggest a deep-rooted connection to spiritual matters and a powerful drive towards self-realization or liberation. The retrograde motion indicates that the native may need to work through past karma related to detachment and sacrifice.
These placements can be challenging, but they also offer opportunities for profound growth and self-awareness by forcing an individual to confront and resolve past issues.

Note ** Basic of Astrology should not be forgotten like if 6th 8th 12th lord is friend of lagnesh then impact with very less