Quote from Kenero;1127802:
That was what I was getting at. It probably has 0 def and 0 prot but it is hard to imagine it hitting that high regardless.
I'm with Kaeporo on this one.
Side Note: Character face models have been updated.
After crunching some numbers it seems that you can deal that much damage with both an Abyss and a Guard Cylinder. The Water Cannon Max Damage reforge can be applied in three places and unlike traditional water alchemic damage, it receives the improved damage multiplier bonus.
I've also found a video of the Duke boss fight. It seems that he has defenses on par with at least Languhiris. He's got a lot of protection which you'll have to whittle down. I've seen him dive underground through his shadow and summon around 30 Black Ship Rats, Nightmares, and Light Gargoyles.
When his health is fully depleted, he'll kneel down and allow you to execute him.
The group I watched took out the last quarter of his health in like 10 seconds but they dealt around 2.5-4k per hit using Way of the Gun.