Masculine, direct-action Kuja constrained by feminine, indirect-suggestion Chandra = fundamentally oppressed and uncomfortable.
The rashi of Karkata owned by embracing, soothing, accepting, nurturing, emotionally sensitive Chandra is the worst possible place for Mangala to be. Mangala (Kuja) is direct and offensive; Karkata (like the crab) is indirect and defensive. Kuja rules the instinctive animal behaviors of the human body. Kuja is muscular movement. Kuja is sexual pursuit and conquest, Kuja is running and racing; Kuja is competition and sport. Kuja is narcissistic, competitive, and needs to win; Chandra is parental, collaborative, and needs to stabilize.
When Kuja is forces to endure an extended stay in Karkata, Mangala cannot express His athletic, winning, fighting, pursuing character in a direct and honest fashion. He becomes anxious and "aggressively passive-aggressive". Mangala disturbs the emotional peace when He is in Karkata. Forced into the home-loving and peace-enforcing world of Chandra, Mangala feels like He is standing in deep water. He cannot move effectively. Mangala becomes scheming and manipulative, desperately looking for slower, more covert ways to achieve His goals.
