Random slightly crackpot theory:
All of the Heralds expect Taln were artificially changed to exhibit their order’s traits, as Taln was an accidental Herald (I think). Therefore, once Taln regains sanity, he will be the only Herald not to have the weird opposite traits thing. Alternatively, he won’t have the oppsosote traits thing because he was the only one of the Heralds who wasn’t “broken” by refusing to return to Damnation. Alternatively alternatively, he has a different sort of madness caused by the torcher, not the long life, as all of the Heralds would have had the long life madness way before, as they were in Damnation for a very long life.