Galarth will clutch herself in pain.

Galarth’s knees hit the cold wooden floor of the bathroom with a thud. The high-pitched scream still echoed in his...her....new ears

A goblin, a stinking, weird looking, freakish, goblin! How could this happen to her? Besides the new goblin were her old nightshirt and trousers that laid in a discarded pile around her ankles. Every last scrap of the proud, muscular paladin was gone. Replaced by this filthy little goblin slut!

She was still staring, trembling in horrified wonder, when the first deep ache bloomed in her belly.

"OOooo~" She moaned.

The ache traveled from her gut then dwelled in her hips. Then it sharpened into a burning sensation. Galrath gasped and bent forward, one clawed hand flying back to grab her own ass—

—and felt her bottom swell.

A thick, heavy pulse rolled through her buttocks. The soft green flesh ballooned outward under her fingers, rounding, filling, growing denser and heavier by the second. Her cheeks parted wider as the new mass forced them apart. The tight little virgin pussy between her thighs was tugged open slightly by the sheer pull of the expanding ass, and a warm, slick trickle of arousal dripped down one green thigh.

“What? What? Nooo! Nooo!” she squeaked in fright. She staggered upright and half-ran, half-waddled out of the bathroom, clutching her growing rear with both hands. Every step made her plump bum wobble. What was happening to her now? There was a flash in her head, a memory filled her noggin making Galrath focus on getting to her library. Out of the bathroom and into the hallway she shot towards her library. Carefully jumping out, causing her buttocks to wobble, the former paladin entered her study.

Inside, the shelves loomed like cliffs. Galrath scrambled up onto a chair, then onto the reading table, and finally began yanking heavy tomes down with frantic little claws.

"What was it, what was it? Goblin lore? Goblin biology?" She huffed. "Goblin Females and their strange bodies, there you go!"

She found the slim tome. Many folks knew that goblin ladies were rarely seen by other species. There was a passage though that explained why. Quickly passing by an introduction to goblin physiology and female goblins and their relationships with males. Galarth found the passage and read aloud.

"Goblin females experience a unique reproductive urgency. If a mature goblin woman does not receive seed within seven to fifteen days (time is dependent on the female goblin's genes) of her last mating, her body begins to store excess energy in the gluteal region. The buttocks, and hips and thighs, will swell continuously growing softer, heavier, and more pronounced in order to advertise fertility and attract males. There has been no recorded upper limit but some goblin ladies have been seen with asses the size of oxen and those that had been recorded were noted to still be expanding though at a much reduced rate. The process accelerates with each passing day of abstinence but eventually plateaus around a week, though some have been noted to plateau longer. Only regular impregnation or thorough sexual release can reverse their expansion and give back their normal buttocks."

Galrath’s red eyes went wide. She turned to take stock of her blimping bottom. Her green face grew a little lighter

A small whimper escaped past sharp little fangs.

She was a virgin goblin girl.

And according to the book, her ass was only just getting started.