I found a way to do something.

If you give all the gold to the tax collector at the Customs, you can get a unique scroll without a description of the effect.

It turns flesh into gold as a permanent state, like petrification.

I managed to turn Jergal into a useless statue. There is a theory that when I get the word of power - kill like Dark Urge, I will be able to use it on this statue and see the secret content. A character petrified cannot take actions and retaliatory actions if self-resurrection is a retaliatory action



Thanks to Larian for Baldurs Gate 3 and the reaction to player feedback