There are three tiers of s84 armor: Vesper, Vorpal, and Elegia. While mostly everything can be obtained in town at the Shop Manager, we've made these items accessible through means of hunting, group instances and raiding.
Tier 1: Vesper
Recipes and mats drop from: Stakato nest, Antharas Lair, Hellbound
Tier 2: Vorpal
Pieces drop from Epics such as Antharas, Valakas, Frintezza, Freya, and Beleth. These also have a chance to drop in Lair of Antharas in the three levels of "pytan room" where you find the daringly difficult High Five Kariks.
Tier 3: Elegia
Pieces drop from Hard Mode Freya. Can also be obtained through the Item Broker's in Aden and Giran.