Fantasy Mansion Expansion Pt 2 (Patreon)

Series: Crossover

Characters: Saeko (Highschool of the Dead), Matsu (Sekirei), Guild Girl (Goblin Slayer), Glynda (RWBY)

Contains: Weight gain, breast expansion, tentacles 

Commission

—

The life of an adventurer eventually led to dungeon diving. Exploring the surface was fun, but the real money was in dungeon diving. Riches replenished themselves, and sometimes rare variants would arise. That’s because the dungeon itself was a living being that lured in adventurers and monsters alike to feed itself. 

Recently, a new dungeon variant had appeared. The initial survey team confirmed it was a mansion-styled building full of riches and…other interesting things. These four adventurers had returned with massively expanded bodies. Heavy breasts, rounded bellies, plump asses, and lusciously thick thighs. Their recounting of the quest, a guild policy, left everyone shocked.

There were no hostile monsters in the dungeon, only tentacles. Those tentacles seemed…friendly. No physical harm was present on the adventurers, and the items they brought back were incredibly high quality. Their fuller figures and valuable items caused other adventurers to flock to the mansion, and each of them left expanded as well. This dungeon was now referred to as The Expansion Mansion and maintained a 0% mortality rating even after a month. This enticed many to journey from across the country to explore their fetishes with no risk. 

This caught the guild association’s attention. Guilds were created to help manage adventurers and those who needed their aid via quests. They also served as an information-gathering association, so the influx of magical items and strange potions couldn’t be ignored.

Thus, a new branch of the guild was established outside the mansion. It gave easier access to food and rest for those who delved into the dungeon, as well as a place to sell or donate newly discovered items that the guild could research.

“And that’s why the guild had us transfer here,” Glynda explained. She was a retired adventurer who had taken a job at the guild. She moved her way up the ladder, and her reputation was spotless. It was no wonder she had been selected as the branch’s guild master. 

Guild Girl had been selected for her positive reputation. She was a friendly face who wasn’t unfamiliar with the sort of quirky characters that sought out this mansion. This job had been a bit of a test, though. “I’m surprised so many people are…interested in this dungeon. Most of them seem obsessed or outright addicted.”

“I can see the appeal.” Matsu, a renowned researcher of magical items, said. “There are some who spend small mountains of gold for custom spells or items to do this. Now there’s a dungeon that gives it to them for free. I absolutely understand them.” She giggled, her glasses gleaming. 

A sudden bell rang. Someone had arrived at the guild. Matsu was the first to stand and made her way out of the break room and toward the front desk. It was late, so this was most likely the last return of the night.

It was obvious that this adventurer had just returned from the dungeon…

Saeko stood at the guild desk. Her purple hair looked more disheveled than when the young woman had left that morning. What was more obvious were her breasts and stomach. Each was an engorged orb, thick and round. 

Saeko’s breasts stretched her top, each boob nearly four times the size of her head. Despite their heft, they were surprisingly perky. Matsu tried not to stare, but just one boob was wider than her entire chest. Saeko didn’t seem to acknowledge their size or the highly detailed outline of her nipples beneath her shirt.

Saeko’s belly was fully exposed, perfectly rounded, and partially supporting her bust. It looked like she had either eaten enough to feed a family of ten, or she was perhaps heavily pregnant with quintuplets. Her stomach was so large that it rested atop the guild desk, partially squished against the surface.

What had Matsu most curious was how calm Saeko seemed. “Um, welcome back. It seems the dungeon dive went well.”

Saeko nodded. “Yes, extremely. I’m here to give my report.” She waited for Matsu to grab a pen and paper. “I believe I’ve discovered a new room. It was down the recently discovered corridor, but it was hidden behind a bookshelf. Inside the room was a pedestal holding this bottle.”

Saeko placed a glass bottle on the counter. It looked like an old-fashioned milk bottle, fitted with a crimped lid instead of a bottle cap. 

“I attempted to grab the bottle when a tentacle ambushed me.” Saeko’s cheeks turned pink. “It stuffed itself between my legs and started to fill me.” She pressed her hand to her stomach and bit her lip. “My stomach filled like a balloon, becoming incredibly taut and round. The pleasure was so intense that I started to push back against the tentacle. I did everything I could to force it deeper.”

Matsu continued to write, but she looked at Saeko curiously. This was a lot more detailed than the usual report.

“I grabbed the tentacle firmly in my hands. It had a strange texture. Soft and squishy on the outside, but I could feel it become firm deeper inside. I have a theory that the tentacles can increase in size based on their prey.” Saeko rubbed her chin as she mused. This caused her arm to squish against one of her breasts. The flesh was so supple that it morphed around the slender appendage like bread dough around twine. “I must have spooked or enticed it because two additional tentacles appeared. Those went for my breasts.

Saeko suddenly thrust her chest forward. “See, my nipples are very engorged and puffy. The tentacles latched onto them, sucking powerfully before they pushed inside. They managed to fill them just as easily as my stomach. The texture shows they’re filled with fat. Perhaps the tentacle secretions cause rapid proliferation amongst fat cells? Go ahead, touch them if it helps the report.”

Matsu had never turned down the chance to squeeze supple breasts. However, no one willingly offered themselves up like this. “Well, if it’s for the report~” She grinned and grabbed Saeko’s breasts. 

It was just as Saeko said. Her breasts were so soft and malleable that they had to be filled with fat. A gentle squeeze caused these massive tits to morph around Matsu’s hands. Fat bulged between her fingers and rolled around her palms with ease. “There have been magic items that increase bust size, but no one has reported this.” She pinched one of Saeko’s nipples, rolling it between her fingers.

Saeko suddenly jolted. Her knees buckled as she was forced to hunch over, a heat and moisture building between her legs. “T-the sensitivity hasn’t gone…nff…down in the slightest.” She had to brace her hands on the desk to support herself. “I-I…had to abandon my chest plate in the dungeon…I kept cumming when I tried to force it on.”

“I’m sure the dungeon has already repurposed it then.” Matsu removed her hands from Saeko’s chest and jotted down the details. “Dungeons gather the precious metals to make treasure from the surrounding ore deposits. Equipment left from adventurers gets absorbed all the same.”

“Perhaps it will return to me enchanted?” Saeko murmured before she shook her head. “Regardless, I wrapped my legs around the first tentacle. That freed my hands for the ones at my breasts. I grabbed each of them, trying to force them deeper. I wanted them to fill me more, and I refused to let go.”

Saeko suddenly looked sad. “It lasted for hours, but I eventually grew weak. My final climax gave the tentacles the opportunity to escape. I retrieved the bottle and left.” She sighed and rubbed her belly again. “I’ll sell the bottle. Please transfer whatever funds you’re willing to my account. I’ll be returning to the dungeon now.” Saeko waited for Matsu to stop writing before she turned and waddled away.

‘Looks like her ass is fatter, too.’ Matsu thought to herself, watching Saeko’s pillowy ass cheeks bounce as the woman left. This was when she realized just how quickly her heart fluttered. Hearing Saeko’s story and seeing her body got her excited. Maybe a little more than excited. 

Incredibly horny was most accurate.

“Oh, that’s right.” Matsu looked at the bottle. Saeko had been so eager to return to the dungeon that she didn’t wait for the appraisal. It didn’t take long, as Matsu only had to cast a spell. 

The bottle contained milk. That was hardly a surprise. However, several effects appeared, too. 

“Increase bust EX+, increase bust sensitivity EX+, milk production EX, increase hips S, increase belly A, and induce arousal S+.” Matsu read them aloud before she grabbed the bottle. She had issued the payment to Saeko’s account, so she should put the milk in storage.

Should.

Matsu instead walked to a nearby coffee machine and filled three mugs. Each was topped off with the milk before she returned to the guild break room. “Saeko made it out of the dungeon. Seems there’s a new room, and she wants to explore it further.” Matsu explained as Guild Girl and Glynda looked at her.

“Again, I don’t understand how people can be so eager.” Guild Girl chuckled and accepted the mug Matsu offered her.

Glynda was so enveloped in thought that she didn’t speak until after receiving her mug. “You don’t need to understand how, only that they are. The more people who come here, the more work we have. Do well, and you’ll be in for a pay increase.” Glynda took a sip, unaware of the milk’s special properties. “If I were younger, then perhaps I would delve in. Just to see.”

Matsu giggled before she drank from her coffee. ‘Well, it seems I have quite the control group. One who can learn why the dungeon is popular, and one who can tap into fantasies she thought out of reach. As for me? I would have delved into the dungeon eventually.’ She thought and tried to keep her cool.

The girls had nearly finished their coffee before Guild Girl spoke up. “Oh, Matsu. You mentioned Saeko found a new room. Was there anything interesting in it?” She grabbed the collar of her guild uniform and shook it a little. She started to feel a little warm.

“Nothing special. A pedestal with a bottle on it. I think the dungeon was experimenting with baiting a trap.” Matsu placed a hand over her stomach. “Tentacles again.”

Glynda rolled her eyes. That was how most of the dungeon dives ended in the mansion. ‘That’s the reason I don’t go in. My hips probably couldn’t take it.’ She thought, remembering how many female adventurers claimed they were assailed by tentacles, being probed and filled. It never failed to make her horny, but she was no spring chicken. 

Now, Glynda wasn’t old, but a rough tentacle fucking would leave her bedridden from soreness more than any weight gained. She closed her eyes to imagine it. The mental image of her body thick and round, roughly fucked by tentacles. It was enough to set her alight. Her thighs squished together, and her chest grew incredibly hot. 

Glynda opened her eyes when she noticed her uniform felt tight. Her eyes widened in shock when she noticed her breasts had grown. Each was the size of her head and growing. The fabric rubbed against her nipples, which caused pleasure to bubble up by the second. 

Guild Girl had also noticed her chest start to grow. She grabbed her breasts inquisitively. The sudden spike in pleasure was so intense that her lower body spasmed. She had cum from one touch. “W-what…” Her thighs started to rub against each other as they gradually thickened. She hunched forward and pressed her chest to her knees. This increased the tension and pleasure. Guild Girl couldn’t help but moan without restraint. 

Matsu felt her lower back twitch and arch, pushing her chest forward as it expanded. She pushed her breasts against the fabric that wrapped around them more tightly by the second. She clenched her fists and bit her lip as she felt her nipples rub against the inside of her shirt. The tingling buzz of pleasure became more powerful by the second.

During this, Matsu rubbed her expanded thighs together. It wasn’t as intense a pleasure as her nipples, but that was fine. Matsu simply focused on everything that felt good as her outfit started to tear apart. The upper buttons of her uniform popped first. Each popped button opened the front of the uniform, exposing more of Matsu’s skin and the full curves of her breasts. 

More buttons popped as Matsu’s stomach started to round and swell. It wasn’t anything like the massive belly Saeko sported, but it was still a soft dome that filled half of her lap.

A few seconds later, her skirt’s waistband snapped. Her hips had suddenly grown wider, but her ass was so fat that the skirt wouldn’t have covered it. The plumpness of her cheeks was more than her belly but less than her chest. It was enough to give her a top-heavy hourglass shape, her breasts the sizable forefront of a very lewd and expanded form.

“Sorry, the milk I used for our coffee was an item Saeko brought from the dungeon.” Matsu apologized, but she smiled as she did it. Her glasses also had the same gleam as when she’d recount tales from the dungeon. 

Guild Girl huffed. “Seriously! How can you apologize while smiling like that?!” She wanted to stand, but her legs were too weak. She wasn’t angry. It was too difficult to be anything but insanely horny. Mostly, she was flustered. Her outfit was breaking apart around her body. The buttons of her shirt popped like Matsu’s, exposing her chest, then her stomach. Her skirt eventually tore free to expose her rounded butt. 

Guild Girl was receiving a crash course in why this dungeon was so popular. Adventuring was traditionally a dangerous profession. This dungeon was completely safe, though. People left expanded or obese, but they were never injured. They always glowed with satisfaction. 

Guild Girl understood why. With all the pleasure in her body, there was no room for stress or anxiety. Every negative emotion was completely smothered by sheer ecstasy. She couldn’t stop her hands. She grabbed her breasts and squeezed. This charged the pleasure, surging it into a blindingly powerful peak. Her legs spasmed in pleasure, thighs rubbing together as she climaxed a second time.

‘I get it now.’ Guild Girl said. She would have said it out loud, but her entire body trembled in pleasure. There was no way to get words out.

Glynda was the only one on her feet. She barely managed this, though. Her body expanded just as Guild Girl’s and Matsu’s had. Her top had discarded all its buttons to expose her breasts and belly. Her skirt strained until it tore in half and slid off her hips to expose the fullness and roundness of her butt cheeks. 

Glynda’s body was alight with the pleasure she wanted. She ran her hands over her sensitive skin, occasionally groping and teasing parts of herself. Eventually, her fingers reached her puffy nipples. One flick was enough to make her climax. 

There was more, though. The tingling in her nipples became more intense. This built and built, pressure mounting until Glynda’s nipples began to drip milk. At first, it was a slow trickle, but it quickly built into a more powerful spray. Every twitch of her body caused another powerful spray. 

Glynda gradually gave in to this storm of pleasure. She hoped her mind would eventually settle, but there was no way she’d seek to reduce her body. She’d submit the order for an upsized guild uniforms in the morning, then she’d try to figure out how to do her daily duties with her drastically expanded chest.

Matsu continued to grin and twitch as she hobbled toward the break room door. She made sure it was locked before she returned to the group. It was clear that their night would be spent enjoying and becoming accustomed to their new bodies. So, Matsu looped one arm around Guild Girl’s and pulled her toward Glynda.

The trio hit the ground with a thud as their bodies became entangled. Matsu readily stuffed her head between Glynda’s breasts, while Guild girl wrapped her thighs around one of Matsu’s legs. Glynda wrapped an arm around Guild Girl’s side and squeezed one of her breasts, provoking a brief torrent of milk from her nipples. 

There, the three girls continued to rub and caress each other, pleasure building as delicate and sensitive areas were more boldly and confidently fondled. 

This pleasure wasn’t wasted, though. Even if it took place outside the dungeon, it was caused by the dungeon’s creation. The energy flowed to its source, and the mansion was further powered through pleasure. 

The results of this would go unknown for a while longer…

THE END