You need to be more specific about the skill or damage in question.

Edit: Cleave dot damage as in endless hail/caltrops = thaum. DoTs are almost always thaum, there is some weird exceptions like wall of elements and warden's permafrost ult effected by master-at-arms.

what cp skill increases the bleed dot?

Oh sorry, brain fart.

The initial hit is master-at-arms and the bleed is thaum.