Use her mouth

"I have spent so much time enduring your insults." You spit the words, your voice carrying a dangerously sweet tone. "Why don't we put that dirty tongue of yours to better use?"

She's not an idiot. She catches on to the double meaning immediately, but before she can even try to protest, you pull her towards you. All it takes is a flick of your wrist and your enhanced magicks **** her body up those steps like a ragdoll. With that same arcane might, you spare the both of you the need to remove any armor plating. Your crotch is exposed with another gesture, causing the fat bloated girth of your cock to spring free with a dull wet thud. The girth alone is bigger than her forearm.

"Y-you can't be serious." She stammers, eyes wide in terror, cheeks flushed bright red. There was a time when she could have resisted your demands, your power. But your triumph brought with it a plethora of new sources of power for you. She is no longer a match for you. Disappointing, really. You've so enjoyed the challenge of fighting her off...

You don't even entertain her defiance. Snapping your fingers, the sound echoing through the throne room, you open your legs wide, letting the powerful arcane smell of your erection hit her in full ****. "If you want your town safe under my reign, you know what to do."

"It's...not going to fit!" She briefly opens and closes her mouth, as if to gauge how much of your cock she can down before it would be too much. Where her body fails, your magic will do the rest. She's not even trying to argue with you for long. She was always a pragmatic - hotheaded but realistic. There's no way out of this without proving herself.
You watch, gleefully, as she crawls forward until she's kneeling between your legs, your throbbing length towering over her like a kingly scepter, its shadow casting her features in darkness. She reaches out , her strong bruised hands trembling once she touches the scalding heat of your cock. Her fingers delicately stroke along your length, up and down, closer and closer to the base, until her hands try and fail to wrap around the massive size of your swollen ballsack. You're blessed with an endowment that would make the most hardened warbeasts of your armies blush - She's not immune to the allure either.

She inches closer and closer, until she's practically pressing her face to it, only a breath's length away from kissing your broad tip. She rests both her hands on your veiny girth and looks up at you, wide-eyed but with a clear expectation there. "Promise me." She says and licks her lips, "Protect my people."
You would have handwaved it away, but you two have history. What harm is there in handing out a little boon...for the right price?

"As long as you're a nice and obedient set of holes for me right here and now, I don't see why I should go back on my word."

She cannot see your grin under the helmet, but your voice gives her good enough of an idea. She rolls her eyes at that and gets to work.

Her tongue is rough, lashing your tip like a gladiator's whip, drenching your cock in a thick coating of her saliva as she's still struggling to even imagine the logistics of fitting you in her mouth. But she's a fighter not a quitter. This is no different to your past battles, she clearly tells herself, just another contest of 'might' to overcome, to be the hero for her people in Blackwater. You're not exactly thinking that far ahead right now, with her smearing all that spit along your massive length and her lips slowly enveloping your tip in an array of frenzied kisses.
While at first, she's aggressive, working off a checklist of things to satisfy you, she's really getting into it just moments later, mesmerised by the potent intoxicating taste of your cock on her lips. It doesn't take her long for the first muffled moans to escape her, just in time for the first inch to pop past her her teeth. There's no room for anything but your length now. She gags as her tongue is squished under the broad throbbing heat of your arousal and she gags again when you briefly buck your hips and batter your cock right into her throat. Not so deep as to do all the work for her, but just deep enough that there's only one way to go for her.

She whimpers, tears streaking down her face, smearing the simple ashen make-up she has in thick streaks that run down her cheeks. She tries to work your length out of her mouth, but you won't let her. In an instant your hand is on her scalp, pushing her down a little for every gag coming from her tight throat. "Keep going!" You grunt and begin moving your hips a little. She feels downright heavenly, flexing, gulping and convulsing around your length, perfectly snug. You're not letting her go until you've had your fill of her.

You settle into a quick but staggered rhythm, working inch after inch into her. Soon you're violently slamming your length past her throat barrier. Her neck is bulging out in the shape of your monstrous cock and she's practically holding on for dear life, hands clinging to your legs for what little support she can still gain. Her tongue weakly twitches against the underside of your length and her neck strains to move in sync with you. But she's nothing more than a doll with a pretty mouth in this moment. You can smell her own arousal on the air now, sweetest nectar dizzying your greedy senses even more. "I should have done this years ago." You grunt and immediately her throat tightens with a stifled moan that vibrates through your entire length.
"Such a good girl. You're practically built to take me like this."
It's so much easier to **** her, when she's got no way of talking back...It's also much easier to lose control that way. At this pace you don't last long, pent up as you are. She can feel your shaft bloat with need, plugging her throat shut completely and finally cutting off that last air supply she could still squeeze in there. She's twitching and trembling as you slam yourself so hard and deep into her throat, your balls are leaving painful red imprints on her chin. With a roar that shakes the foundations of your halls, you hilt yourself in her mouth and pump a thick alabaster flood of potent seed right down her throat and into her gut. She goes limp, cumming on the spot, eyes rolling back mindlessly in their sockets. She can hear your cum churning in your balls, pumping load after load into her until she's dizzy from the lack of oxygen. When the flood finally lets up, you pull back just enough so that she can breathe again through her nose, but selfishly, she tries to pull herself off of this lustful gift you've given her, trying to free her mouth from the girth lockjawing her in place.