Core rules, p. 154. Advantage: I'm Taking You With Me.
"Spend a Hero Point to have all damage that you do this Round increased by the number of Dramatic Wounds you have."
So my player has taken 2 Dramatic Wounds, makes 6 raises & spends a HP. On count 6 he spends 1 raise to deal 3 Wounds (1 for the raise +2 for the advantage). Count 5, he does the same thing, and count 4, etc etc. Over the Round his 6 raises translate into 18 Wounds.
Ok, that's a little overwhelming, but makes more sense in a way than his turning 6 Wounds into 8, because its a 5 point Advantage, it costs a HP, and lasts only 1 round. All agree?
So rather than charging down their enemy with a double-handed axe & dealing massive damage in one hit, it is more like someone repeatedly stabbing their enemy with a small knife and twisting the blade?