Do damage over time effects stack?
The ability "Rend" makes your target bleed for 3 second. What happens if you consequently use the spell? Will the damage stack or is it a waste of rage to use the spell consequently?
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You will refresh the timer on the rend debuff, not apply a totally separate effect. However, you will still get the initial damage, and if two separate barbs apply a rend, you will have 2 rend debuffs.