Dive Underwater And Acid-Blast Him From Behind! (Non-Anthro, Adult Black Dragon.)

What made this knight think he could attack a black dragon in its native habitat?

You dive off the balcony of the abandoned castle in the swamp where you've been living for the past week and into the former moat, which now connects to a number of aquatic tunnels networked throughout the local area. This, in turn, lets you pop your head up behind this moron, and blast him in the back with an acid jet. He goes down, screaming in pain, and you rise from the swamp to stalk over to him.

"You are very stupid. I could kill you, and the venom in that acid may yet do so, but I'm trying to 'turn over a new leaf' as you humans say, so, I'm going to let you live if you can. I'll even take you back to my castle and help you recuperate, but before I do that I'm going to strip you of your armor and weapons, because I am not as stupid as you are." You explain, and proceed to do so while the paralytic toxins in the acid keep him from resisting.

As you walk back you wonder about what to do with your moronic captive when he's recuperated: wait, is 'he' actually a he? The face is very androgynous, and the long hair gives you pause. Moreover, what gender are you?