After boarding the boat from the Underdark beach, a boat captained by Corsair Greymon will sail up alongside the party's boat. Greymon will come aboard, and the player character will have to pass a check or attack Greymon and his crew. Passing a DC 15 Athleticscheck to push him into the water will kill Greymon, sinking his inventory to the bottom of the sea, while initiating combat with the surviving Duergar; this will also garner approval from Lae'zel and Astarion. In a chest aboard Greymon's skiff is the Intransigent Warhammer.
If Greymon sails into the Grymforge with the party, he can later be found and traded with in the area where deep gnome slaves are digging out Nere. As a follower of the Absolute, he will side with Nere if the party chooses to fight him.
Normal weapon damage + Superiority DieWeapon damage
Spend a superiority die to deal Weapon Damage + 1d8 Physical damage and potentially force the target to drop the weapons they are holding.