The Undying Armor Set

The The Undying armor set can be obtained by through Kai Zykken as a randomized reward for level 75+ players. This set is wearable by characters on either faction, who are level 75 or higher, but is only wearable by Sith Warriors* and Jedi Knights*, even in the Outfitter tab.

Kai Zykken Armor

Kai Zykken, a unique vendor located in the Supplies section of the Fleet, sells an item called an Unidentified Onslaught Set Bonus Gear. Kai Zykken Gear Guide.

Legacy Bound

Legacy bound armor is armor that can be transferred between your characters on your server. Pieces of the The Undying set can be obtained on one of your characters, and then sent to another one of your characters on the same server. you can also stamp Legacy-bound armors into the Outfitter tab for as many of your characters as you'd like without the item being stuck on one character.