Force of Will is a powerful ability to defend one's mind against the attacks of another powerful Force user. Once the practitioner has learned the ability, the mind is turned into a proverbial minefield for those who would attack it. Attempts to break into the mind of those who wield it backfire, and the mental attacker will find their minds trapped with seemingly no means of escape.
Force of Will is an ability designed by Kravos in order to protect the myriad of secrets that are hidden in his mind. He has found a way to turn his mind into a mental labyrinth designed to hide things from allies and enemies alike. Any attempt to insert thoughts into the user's mind or extract them out will find the attacker's mind trapped, leaving those of lesser power brain-dead and those of equal power to black out until their mind is released from this prison.
This ability is designed to protect the user from illusions, mental attacks of all different kinds, and extraction of intent, feelings, or information from the minds of those who have learned it.
Due to the inherent intent to trap, destroy, and harm the minds of others, this ability is exclusively Dark Side in nature and cannot be learned by those who practice the Light Side of the Force. Although a passive ability, there are limits to mental resistance. Multiple Force users of equal power are capable of powering through the mental walls of the user, but at high cost. Even the slightest mistake can cause the minds of those doing the searching to be trapped indefinitely and breaking the mind of the user will often permanently claim the mind of at least one of the interrogators, intentionally extracting a high cost.
Force of Will is an ability that must be self-taught through extensive meditation. As there is currently only one known user, the inspiration for this power would likely come from Kravos himself as he designed it as a warping of a power he learned during his days as a Jedi Shadow - Force resistance.
As with all things, it has become twisted by the Dark Side of the Force and rather than simply defending the user from mental attack it also offensively traps the enemy. Fortifying the mind in this way does, however, require an incredible willpower that is possible only to those who have obtained true mastery of the Dark Side (Level 4).
This is designed to be a capstone perk for Kravos and is therefore restricted to those who are level 4 and want to choose this as their capstone perk. It was inspired to be a Dark Side twisting of the power Force immunity, which creates a "mental fortress" for Light Side users. Because this is an inherently Dark Side power it is designed not only to protect its user but simultaneously destroy the minds of those who attack.