The Sphere Grid Expansion (part 1)

They’d been training in the Omega Dungeon for days on end when Yuna suddenly found her Sphere Grid growing outwards. Confusion bubbled among the little group of warriors. Was this a reward for completing the whole thing? Why had no one told her about this?
Nevertheless, she soldiered on with the additions. After all, she needed to be as strong as she could if she wanted to defeat Sin, right?

“Hmm,” She frowned, plugging an Ability Sphere into the latest node on the Grid. It lit up with its trademark clashing noise, and suddenly she’d learned this whole new ability.

“Whatever could ‘Expand’ mean?” She muttered, wheeling through list upon list of abilities to find it nestled right at the back. These things usually weren’t cryptic; ‘Fire’ made fire, and ‘Cure’ cured things, so it stood to reason that ‘Expand would-“

“I’ll give ya a hand, Yunie!” Rikku appeared, squeezing her shoulder. “Need a Guinea pig? Here I am!”

“Umm…” Yuna hesitated. Was that wise? Testing out an unknown spell on her dear friend, and guardian no less?”

“Foolish,” Auron huffed. “You have no idea of the consequences, Rikku.”

“Well yeah, but at least we have some control over it if we test it on one of us.” Rikku shrugged. “It sounds like a buff. What could go wrong?”

“…as you wish,” Auron’s eyebrow arched. “Just remember that we’ve no shortage of fiends for you both to play mad scientist with.”

The most experienced guardian divorced himself from the situation, his footsteps echoing through the cave.

“Huh. What’s up with grumpy gills?” Rikku pointed a thumb over her shoulder. “Either way, forget about that. Hit me, Yunie!”

“If… if you’re certain.” Yuna gulped down her uncertainties. Accessing the spell within White Magic, she summoned the essence of ‘Expand’ and felt its energy flowing through her body. That energy was concentrated into her hand and propelled into Rikku, who shivered from the contact.

At first, nothing happened. She looked herself up and down, expecting changes, but there weren’t any to be seen.

“Maybe it’s a dud?” She shrugged.

“I’ll get a Dispel ready, just in case.” Yuna said. The last thing she needed was for her cousin to blow up on her or something. Something told her Cid would be weirdly understanding, but that was a different matter altogether.

“Nah, it’ll be fine Yunie, what’s the worst that could hap-“ Rikku began, only to stop mid sentence. She tensed her knuckles as an odd tingling ran up her arm, and then through her body. Something within her felt like it was being stretched and unravelled, followed by a stomach gurgle and nausea.

“…okay, I dunno if I like this.” She said thickly. “Still got that Dispel handy?”

“Y-yes!” Yuna responded, channelling a second spell in preparation. Before she could cast however, she noticed something… odd about Rikku.

“Hang on,” she said, and walked closer. “Since when were you taller than me?”

“Since never?” Rikku frowned. “Wait, that’s what this does? C’mere Yuna, let’s measure!”

Taking in a deep breath, Yuna drew herself to her full height, but Rikku was a full head taller than her now. She must’ve grown a good six inches in no time at all. What benefit was there in having someone grow just a little bit?

“Huh. Guess I can reach stuff off high shelves at least now?” Rikku smirked. “Better than 5 foot 4, I’ll give you-“

Suddenly, there was a jolt, and the teen jumped up another few inches. Steadily growing upwards, there was the creaking of protest as her shirt began to strain. It was a few sizes too small for her now, after all.

“Huh. So much for six foot.” She gulped. “How big do you reckon I’ll get, Yunie?”

Another lurch, and another jump in size. Her shirt tore at the chest, and her bra strap was visible to the world.

Yuna gasped. “Avert your eyes!” She cried, turning around to block off what she could. Lulu and Kimahri were perfectly happy to oblige. Tidus and Wakka, less so, but they still did out of respect for their summoner. Next thing Yuna knew, there was a rumbling, followed by a cry from Rikku.

“Whoooa!” She cried, spilling out of her clothes. Her shirt, shorts, and even bra simply tore away from her ever expanding body, and the giantess fell onto her gargantuan ass, spreading her legs out in front of Yuna.

“Rikku!” The brunette cried. “Oh, Rikku! I’m so sorry!”

“Sorry?” Rikku said, glancing down at her. “Why sorry, Yunie? This is amazing! Look how tiny you all are!”

“And look how big you are!” Yuna gestured with both hands. Rikku must’ve been a good twenty feet tall now, stooping her head against the cave ceiling while revealing every inch of her body to the world.

“…and how naked you are!” Yuna blushed, shielding her own eyes. Not that she hasn’t seen it before, but she could at least spare the girl some dignity.

“Huh. Yeah, I guess I am. And you’re right in the money shot, hey Yunie.” Rikku said.

“That’s… a word for it,” Yuna mumbled.

“So uh, I guess this is a weird thing to ask, but…” Rikku bit her lip, “before you fire up that old Dispel, would you mind doing me a big favour?”

“A-anything, Rikku?” Yuna craned her neck upwards. She could still see thighs in the corners of her eyes, and there was no escaping the breasts, now big enough to flatten her, but she did her best to look her in the eyes. Whatever the request, she could accept it with dignity and decorum.

“Would you uhh…” Rikku grinned. “Play with me?”