Background
Legendary items comprise the games highest tier of gear. The Asian versions have lower level (pre-level 50) ones that provide overlap in the gear progression. These lower level legendaries (with yellow color/text) were removed from Trion's version due to the massive streamlining of the game systems that Bluehole Ginno did.
The original Korean release was a model for stash clogging consumables (common in Korean game design) as well as slower character leveling progression. While the Korean and Thai version of the game share a lot in common, modifications were still made for the Thai version such as the reduction of inventory clutter (by reducing the number of consumables), faster leveling, and minor graphical changes to take into account cultural differences.
Trion's version has significant changes including an artifact socketing system (gems are used as artifact enchanting material), larger reduction in consumables, faster character leveling, class based battlegrounds, removal of most last hit based mechanics/rewards, several quality of life enhancements including healing globes, ability to combine more talisman cards (10 versus 5 at a time), additional UI/game controls, 12-free character slots (added after the mega-server transition).
As of this writing, it is not known how Trion's level 60 Legendary gear system will work. The following will contain an overview of how it operated in the Asian versions. This is specifically pertaining to the orange color/text tier of legendaries known as Uniques in the Korean version (the Thai version still referred to these as legendaries).
-- This section is a work-in-progress