@ MonarchX: You can cure you entire team from rot by approaching an unused starstone. There is one at the end of the Immaculate trials, one by the volcanic area in Cyseal (by the tree with the dead immaculates), and one in King Boreas treasure room in Hiberheim.

@GawainBS: You can get many T-Weapons from the Immaculate Secret Village (can enter once completed the Immaculate Trial and have Loic's trap door key and his enlightened amulet). I also found a unique T-weapon at the Immaculate Temple in Luculla North (dropped from one of the fire or earth demons that you fight there), but this may just be by chance.