I am a DM who is planning to have the party finally face off against a criminal mastermind whose signature spell is Modify Memory. However, the party rogue is in possession of a Ring of Free Action.
One of the effects of the Ring of Free Action is to make it impossible for magic to reduce your speed:
While you wear this ring, difficult terrain doesn't cost you extra movement. In addition, magic can neither reduce your speed nor cause you to be paralyzed or restrained.
The Modify Memory spell causes the target to be charmed and incapacitated for the duration, and one of the effects of the incapacitated condition is the inability to move.
Does the Ring of Free Action provide immunity to the incapacitated condition if it was caused by magic?
Best Answer
No, the ring of free action doesn't prevent being incapacitated
The incapacitated condition is separate from the restrained and paralyzed conditions (it being inflicted by the latter is irrelevant here) and is not a reduction to speed.† Thus, neither of these effects give immunity to being incapacitated.
If the ring had given immunity to the incapacitated condition, it would have said so (probably by listing it among the other mentioned conditions).
† The incapacitated condition is inflicted by some other conditions (paralyzed, stunned, unconscious) which do prevent movement. However the full effect of the incapacitated condition alone is (per Appendix A of the PHB/Basic Rules):
In 5e, movement is wholly separate from actions (and reactions).