The Weapon Mastery (also known as the Weapon Specialization) is a system that allows the Envoy to improve her battle performance in many levels. The Envoy can choose between two paths, generally called right path and left path.
This system is unlockable automatically when reaching level 60. The interface can be reached through Skills (K) under the tab Weapon Mastery.
For more information about each class' path, please refer to their individual page.
On every class and path, the improvements are generally:
A new skill.
Improvements of two existing skills.
Passive bonus stats.
These paths can be leveled up by gaining experience while defeating mobs (both inside and outside dungeons) and bosses. The maximum level of the paths is 50 for each path.
For each level it raises, the Envoy gains 1 points to accumulate on bonus stats. The max amount of points that can be earned is 100 (with both paths at level 50). When gaining over 30 points, the main class icon on the character bar will glow blue. When gaining over 60 points, the main class icon will glow green instead.