Treachery is intended for the Assassin class. Although meant for Assassins, any class can benefit from the chance to cast Fade or the massive Increased Attack Speed, making this a nice armor to keep in the stash if you lack resists or damage reduction.
It is commonly used for the Treachery pre-buff effect: Take treachery armor on and stand in fire until Fade procs for resist boost (60% resist all, 15% damage resist) for almost 5 minutes (288 seconds), then swap your primary armor back.
Despite its inexpensive cost, when made in an ethereal elite armor, this Rune Word is one of the best Mercenary armors in the game since the increased attack speed greatly increases the mercenary's damage output.
5% Chance To Cast Level 15 Fade When Struck
25% Chance To Cast level 15 Venom On Striking
+2 To Assassin Skills
+45% Increased Attack Speed
+20% Faster Hit Recovery
Cold Resist +30%
50% Extra Gold From Monsters