Take the Mistress of the Depths by the ass.

You look her straight in the eyes and speak your answer bluntly. "Your ass."

She flinches. Though not surprised, she does flush. It's a humiliating demand, though she also would rather perish than not uphold her pride, even if it seems counterproductive to defend one's pride by taking it up the ass. She slowly stands with trembling legs, steps over to the desk once again, she places two hands upon it. With just one eye, she looks back to you in an almost pleading manner. The cute expression you read is strange at first, given who it's coming from, but she's submitting to your request with ease. Her word really is unbreakable. Even the mighty Demon King is willing to receive it between her cheeks.

And quite the pair she has. Her legs are slender, and her ass is soft and perky. Not to make her wait much longer, you approach with your erection leading the way. You grab her rear and give it a playful smack, and when you do, she bends over forward.

First, you push the head against her opening. Then you lean forward to whisper into her ear. As an elf, they're extra sensitive. You watch as it twitches to your breath. "Are you ready?" you ask quietly.

"Y-Yes. Do it," she whispers back.

The overwhelming tightness of her ass brings a moan from your lips. You stretch her open, pushing deep inside as she yells out, mostly in pleasure. A smile curls up her lips, and after bending over moreso, she grasps the other edge of the desk and nudges her ass back even more, as if to ask, "Deeper please," by motion alone. You go all the way into her ass and groan, then back out to begin slow, sensual bucks of your hips.

Each smack against her cheeks syncs with her moans of pleasure. You once again give her a spank. Despite leaving a red mark behind, she seems more than happy to take that as well. Her hips move with yours, as you gradually pick up the pace.

After you've sped up a little, you caress your hands down along her body, with one moving up her inner thigh. You then touch upon her pussy, and begin to rub your thumb around her clit in a circular motion, perfectly in line with your movements between the cheeks of her ass, and with it all together, she melts in your embrace. Certainly the captain's quarters will need a cleaning after the two of you are done with it. She whimpers with delight, already filled with so much pleasure that she could erupt.

"I bet you that you'll cum again before I've even done so once," you whisper again, making sure to enunciate each syllable, and at the end, you blow gently right over her ear. At that, she audible moans. It something that seems to stimulate her greatly. So you then pinch your lips around her pointed lobe, tickling it with your tongue.

"Aaahhhh f-fuck~! No, no I am! I am going to, yes! Th-This is embarrassing. I cannot hold b-back! Aahh, mmmm~!"

"I'll finish the second after."

"... In m-my ass?" she asks.

"As much as will fit."

"F-Fill me. Fill me until I o-overflow!"

Taking her request, you absolutely take that ass in full with no holding back. Your finger plays with her pussy, and your other hand gives her an occasional smack. Right there, over the desk of the captain's quarters, you take the great Demon King Gwynevere, and all she wants is more of you. Once you've reached the quickest speed you choose, she's a mess on the tabletop. Drool runs from her lips, and she can hardly grasp at the edge anymore. Through a cascade of gasps and moans, her sounds of ecstasy finally reach a crescendo. "Yes, yes~!" she begs. "Do no stop or I swear I will--Aaahhh~!" And with that, she cums.

You keep your word as well and finish straight after. Through the tight squeeze of her ass, you throb hard, filling her insides with all you have. The sensation causes her orgasm to become even more intense. She slams her fists down on the desk, cracking the wood, as you gradually finish at last. Your body loosens up, and the pulsing stops. Her body continues to twitch, but you allow her relief as you pull away. Though when you do, she sinks down onto the ground panting.

"So, did I win?" you ask.

She turns back and attempts to stand, though seems to be unable. "N-No."

"What do you mean?"

Then at last, she pulls herself up to her feet. She steps towards you, slowly at first, but then grabs you by the chest and begins pushing you towards the doorway. "I am not finished with you yet... A real man finishes more than once, right?"

"Are you sure your ass isn't too sore?"

"N-Not my ass!"

Before you know it, you're thrown through the door, and in her embrace, she hurls the both of you off the side of the ship.