Exploit Vulnerability

The rules for the Exploit Vulnerability action can be found here

The Exploit Vulnerability action is handled through a macro found in the "PF2e Exploit Vulnerability/MySurvive's Thaumaturge Macros" compendium. To use the macro, the Thaumaturge must select their token and target the creature they want to Exploit Vulnerability against, then run the macro. The result of the roll follows the rules of Exploit Vulnerability, causing the Thaumaturge to become off-guard on a critical failure, applying Personal Antithesis on a failure, allowing the Thaumaturge to choose whether they want to exploit a Personal Antithesis or Mortal Weakness on a success or critical success, and providing all of the immunities, weaknesses, and resistances (and their exceptions) on a critical success.

Once the roll has resolved, it will put an effect on the Thaumaturge and/or the target based on the degree of success which applies a weakness to the target and denotes which creature is the target of Exploit Vulnerability (important for feats like Sympathetic Vulnerabilities).

The weakness caused by Personal Antithesis or Mortal Weakness is calculated with the PF2e system's IWR engine, so it happens during damage application. It will not show when damage is rolled, only during damage application. If the damage is not calculated properly, ensure that IWR is turned on in the PF2e system settings.