Mindless Voice
One of the so-called Nine Shadows, this taboo Tarot ability takes away someone's self-restraint and lures out their deepest desires. This will directly manifest in rants, not keeping possible consequences in mind. If confronted, the affected individual may turn violent, but mostly they initially rant and expose their deepest secrets and desires.
While at first glance, it seems like Mindless Voice takes away self-survival instincts, the truth appears to be slightly different. Rather than not caring about consequences, it appears a victim will not even realise consequences exist anymore. Analysis of witnessed rants supports this interpretation.
While Mindless Voice is a taboo ability, it is a bordercase when it comes to the Scrolls of the High Priest, as it does not override Free Will. Instead, it disables inhibitions and self-awareness. As such, while controversial, it is not considered a Crime with Extraordinary Abilities.
Definitely treading murky water. Ethically. Well done. It makes one ponder the implications of such a spell and how dark it could get. I can easily see how this would be taboo.