| Synonyms = Drive Insane, Words of Madness, Heretic Speech, Devil's Tongue, Possession

| Prowess Prerequisites = [[Manipulative]], [[Trickster]], [[Charismatic]], [[Interrogate]], [[Knowledge (apothecary)]], [[Knowledge (heresy)]] or [[Poison]]| Official? = NoYes

Using exactly With a poison, carefully chosen words or a painful truth revealed, you instil doubt and uncertainty in your target. Slowly cracking the right words core of their soul.  Depending on how familiar you are with the target and depending on the strength of his beliefs, it may take few sentences or a long conversation. If the right tonemaddening attempt is successful, the target will either cow and sob, try to attack you instil doubt violently or feel eternally grateful for your help, then it will permanently suffer the effects of [[Insane]] or [[Lost Faith]] depending on its personality (only the bad effects without any advantages).  If used several times on the same target, he will fall deeper and deeper into madness, to a point where he loses all links with reality. You may chose to influence his madness in certain directions.  The Game Master may rule that a person is special and uncertainttycan't be influenced by this Prowess, he has to warn you before using the Feat. In particular, this Feat can't be used on someone with the [[Courage]] feat.