A most important aggro-management skill for all warriors who wish to improve their ability to tank mobs.
Functionality
Defiance increases the threat generated by your attacks and abilities in [Defensive Stance]. It is a passive Protection talent, and is always active. The threat increase is multiplicative with the Defensive Stance threat modifier.
Rank table
Rank
Threat
Expertise
1
+5%
+2
2
+10%
+4
3
+15%
+6
Notes
For a tanking Warrior, Defiance is a very useful ability. It increases the Warrior's base threat multiplier in Defensive Stance to 149.5%. This multiplier applies to all threat produced by the Warrior, from auto-attacks to abilities with innate threat such as [Heroic Strike], [Revenge], [Sunder Armor], [Shield Bash] and [Shield Slam], and the damage components of these abilities as well. It applies to [Demoralizing Shout] and [Battle Shout] as well.
As of Patch 2.3 it also grants +2 points of expertise per talent point invested while in Defensive Stance. Starting in Patch 2.3.2, the expertise bonus applies in any stance.
[Defensive Stance]. It is a passive Protection talent, and is always active. The threat increase is multiplicative with the Defensive Stance threat modifier.
[Heroic Strike], 
[Revenge], 
[Sunder Armor], 
[Shield Bash] and 
[Shield Slam], and the damage components of these abilities as well. It applies to 
[Demoralizing Shout] and 
[Battle Shout] as well.
