Versatility, secondary stat:
Increases all of the damage and healing you deal, as well as reduces all incoming damage you take.
Avoidance, tertiary stat:
Reduces all AoE damage you take.
Multistrike, secondary stat:
Every time you use an ability two dices are rolled, each have a chance for your ability to occur an additional time for 30 % of the damage/healing, meaning each time you cast Shadow Bolt you have a chance to cast 1-2 extra Shadow Bolts for 30 % of the main Shadow Bolts damage each for no extra cost.