[X] The Soul-Scarring Embrace, a spiritual venom which creates a traumatic vision and sears it into its victim's psyche, forever associating thoughts of violence and the martial arts with overwhelming dread and horror in their mind.
This seems like the most 'Merciful' choice.
It really isn't
It's the most cruel thing you can do to someone who's built their life and pride around violence--to strip the of the capacity to feel pride in the might they've built in life--strength enough to crush gods.
To merely cripple an arm is something the dedicated can attempt to correct. To infuse them with agony whenever they exert themselves can be controlled. These are not correct--not for an art of this potency as used by a Solar turned to war, but one can imagine it, and still carry on.
This is the only one that permits no such luxuries. "That which you dedicated your life to is as ash in your mouth, go home and sin no more."
But people like this? Those who actually deserve this technique be used on them?
If they could be satisfied living a peaceful life, they wouldn't deserve to have this used on them.
Kill the ambition and the dream, no less can suffice.