What are these corruption stacks?

I just spent some time in the Brand in the Fields of Ruin. While I was there, I managed to attain 12 stacks of "Corruption", for which the tooltip says only "Your conditions do more damage."

Are these harmful to me in any way? How do I get them to go away?

Solution 1:

It would appear that you're using a weapon with a Sigil of Corruption.

This will increase the amount of Condition Damage you deal with every stack, up to a maximum of 25 stacks. Stacks are obtained by killing an enemy with said weapon.

It is not harmful to you in anyway, but rather, it is beneficial! If you want it to go away, regardless, simply zone and you will lose all stacks you have acquired.