As well as powering my body, it also changes it.

"Ah...ah....aaaahhh...", the naiad moans out in time with every thrust you make within her, the warmth and wetness of her hungry cunt made more heated and wet by the fact that you'd already spilled your seed within her once. It is an odd sort of sensation, using your own semen as further lubricant to penetrate the water nymph's womanhood again and again. Yet it seems to work well as you feel yourself somehow reaching deeper into the nymph's depths, piercing deeper with every thrust you make.

You realize, however, that the true reason for this is that you are penetrating deeper because you are growing. It is an odd tingling sensation like you've never felt before, but slowly, you feel that rigid length you thrust hard inside of the nymph's heated depths growing in girth and length with each thrust you make. It is an odd feeling and you know you should be horrified by such a change in your body, but you are too drunk on pleasure and power to feel anything but further ignited lust as you drive your changed cock harder and faster into the nymph.

The naiad feels the growth as well and her reaction is also not horror as your deeper penetration and your further stretching of her inner walls causes her moans to grow in intensity and pitch. The increase in your size along with the continued grip of your gauntleted hand upon her throat making that aphrodisiac-like dark energy into her body sends her over the edge fairly quickly, giving her over to that climax you had not managed to give her during your initial fucking of the curvaceous beauty.

"Ahaannn! Yes, ah, yessss!", she cries out as her inner walls clench tight around your cock and milk your rigid length for all she is worth. And this feeling, another new feeling for the virgin male that you are, quickly pulls you over the edge along with her, your muscles tensing and your voice leaving you in a ragged moan as you again shoot your load within her. Despite having already cum once before this, your climax this time is seemingly longer and more intense as you spill a larger volume of your seed within her depths. Even your cum seems different, somehow hotter and thicker as it escapes you in greater volume than before.

The nymph moans and shudders at the feeling of you filling her with your thick jizz once more and she starts to sigh in ecstatic relief as her orgasm ebbs along with your own...but she is not allowed relief for long as, after only a brief few seconds, you start to thrust inside of her again. She moans throatily at the feeling of you stirring even more hot, thick spunk inside of her already dripping sex, but looks at you in wide-eyed shock as your virility and stamina surprises her.

"S-surely, you can't, ah, c-can't b-be, ah-ah-ahhhhh, s-still h-haaaarr-r-r-r-rd?", she moans out, but the question is moot as she can feel very well you are still hard and eager to continue your fucking of her pleasurable snatch. She seems to want to ask you to stop and give her time to catch her breath, but the subtle tightening of your hand at her throat and the increased fervor of your thrusts make it impossible for her to voice anything but another broken moan of pleasure as you well and truly pound her pussy.

Each thrust inside of her makes a lewd, wet sound as your own cum and her feminine juices mix and froth around your pistoning length. Her body, supple and curvaceous, shakes with each hammering thrust you give her, her heaving breasts bouncing pleasantly and her wide hips jiggling slightly with the impact of your groin into hers. Your bare hand goes down to grip one of those wide hips, digging your fingertips into her supple flesh tightly enough to make her cry out in mingled pain and pleasure as you slam yourself into her again and again.

Time passes, minutes melting into hours quite quickly, and, finally, your indefatigable lust finally seems satisfied as you spill your seed inside of her for the fifteenth time. Your fifteenth climax is joined by the nymph's...well, you lost count at twenty, but, judging by the way she lays on the ground with her eyes hazed and senseless and her body limp and trembling, you can only imagine it had been more than she'd been assaulted with before in her existence. Her feminine form is pliant and helpless below you, her breasts slick with sweat and her hips touched with bruising where you gripped her hard. Moreover, one can tell that you'd spilled an immeasurable amount of your semen within her as you can almost see a swell in her abdomen where your abundant seed sloshes inside of her. Each load you'd shot within her had been more voluminous than the last until you thought her full to bursting.

It is perhaps a good thing, then, that you finally feel like your lust is sated and, finally, you pull your cock from her ravaged cunt. Your prick, still hard despite your lust feeling cooled, escapes the nymph's sex with a wet pop and, as though you'd breached a dam, a stream of your own cum flows out of her to puddle on the ground beneath her thighs and ass. You, panting and trembling yourself, finally push yourself away from the nymph and fall to a seated position on the ground in front of her. And, with your lust cooled, you feel a semblance of sense coming back to you.

"W-what did I just...do? What just...happened?", you whisper to yourself as you look at your own body, finally finding it in yourself to be alarmed about the changes in you. Your cock, still hard despite having cum so many times, now stands at ten inches long and has to be seven inches around in girth. Not only that, but your testicles have grown as well, each having once been about the size of a peach pit but now grown to plums. You can also feel your ballsack churning with cum despite having reached climax so many times before. You've become something of virile monster and you can only wonder just what it means that you would change in such a way.

You are quick to tuck your cock away as best you can, lacing your breeches to confine the still erect part of your body as much as possible. You feel somewhat better now that that part of you is put away, but, as you look to the nymph, you feel something else in you. Another urge. A dark urge within the back of your mind that has the gauntleted hand at your side clenching and unclenching.

Now take her completely. Claim her. She is yours., you hear something whisper and your body moves as though on its own as you once again lean over the nymph. This time, however, there is no sensuality in your position as you lift your gauntleted hand with the gleaming sharp tips of your fingertips outstretched like a blade. The ends of those sharp claws gleam in the dark cave and you feel a different sort of lust, a lust for blood, flow into your mind.

Take her and claim her, the strange whisper said, but you somehow knew that it wasn't meant in the way you already had. No, the whisper meant something else. And, as you bring your hand down towards the nymph, what that meaning was becomes crystal clear in your mind.