Mastery (formerly known as Totem) is a new addition to the 1.7 patch where it adds a new playing system to the game, where you have masteries that have skills that once activated reduce enemy's Attack, Crit, or Defense, or increase your own stats.
Under Mastery tab there is also Astral Power *Click on page for further information on Astral power*
Totems/Masteries, tier 1 stats
Merman Thorn Lv2
Attack all enemies and reduce 22% armor of them, last for 3 rounds
Explosion Nova Lv2
Attack all enemies and boost 22% armor of all your heroes, last for 3 rounds
Chaos Axe Lv2
Attack all enemies and reduce 22% ATK of them, last for 3 rounds
War Hammer Lv2
Attack all enemies and reduce 22% CRIT of them, last for 3 rounds
*Information for masteries after Therianthropy will be available in future patches
Soul Stones are used to level up Masteries/Totems. Each soul stone provides 3300 experience with a chance for a 2x, 4x or 10x proc. Soul stones can be bought in the Shop for 80,000 gold each or collected from elite dungeons from Snowberg Mtn. onward.