The way this Build works is that you'll use the regular attacks of Hand of Malenia to deal with regular enemies, two-handing it in order to gain max damage and keep your equip load a bit lighter for more armor with higher Poise.

You'll use Waterfowl Dance on tough to kill enemies, packs of enemies and Bosses, using your high Poise and hyper armor of the skill to strike them repeatedly for very high damage, triggering Millicent's Prosthesis and Winged Sword Insignia, boosting repeated L2 damage.

Stamina is an issue for this Build because Waterfowl Dance eats it up, and you likely won't be able to use 3 consecutive L2 pulls twice, without waiting for your Stamina to replenish. Use Greenburst Crystal Tear when facing Bosses to keep your Stamina high, so you don't run out mid attack.

Unlike other Katana Builds, Hemorrhage doesn't play a huge roll in this Build because Waterfowl Dance doesn't build up Bleed fast at all, so don't worry about it, and don't try to maximize Bleeding Build Up.