Vehemence

Vehemence: Vehemence is a buff that adds Strength and damage, and above 100% mastery adds Constitution as well. Its effectiveness scales with Consitution. Here is an example at 150% with ~390 Constitution (note that the duration will be slightly longer than shown here):

   vehemence                   - strength +47 (11:41)
                               - constitution +16 (11:41)
                               - damage +23 (11:41)

From the helpfile:

Usage: vehemence

Ruanbaeres display anger in a variety of ways, this is the most common. 
Vehemence draws from the nature of ruanbaeres allowing them to maintain a 
level of rage even outside of battle. A ruanbaere can use vehemence to 
temporarily increase their strength and their applied damage. As vehemence is
not combat oriented it draws from the ruanbaeres constitution to maintain 
their anger for long durations of time. The higher the ruanbaere's 
constitution the more strength and applied damage they will be able to 
gather. As the ruanbaere becomes more experienced the longer they will be 
able to maintain their vehement nature.

It has been rumored that this ability improves in power for users who exceed
100% ability mastery.