We drunk in the shocked faces of our family as they looked up at the lofty Rachel. They barely reached her lower thigh, and even crouching she towered over them. The match of inspiration was lit. It came as no shock to me when, just a few minutes after explaining what triggered Rachel’s surge in stature, Mom began gaining height. Rachel had to step back as Mom filled more space. The maternal giantess’ evolution stopped a hundred or so feet short of her daughter.

Mom laughed when her scanning eyes caught her short husband and youngest child looking up at her in another layer of awe. Her hands went from her hips to her substantial breasts, pushing them upward. Letting her tits drop back down in a hypnotic wobble, she sighed in deep satisfaction. Looking at my twin’s hand, Mom said, “This is amazing, darling.”

“And it’s just the beginning, Mom.”

“Yes, it is. In fact, if we’re going to reach our potential, I say it’s about time we start to gather energy in mass. We have thousands of animals at our disposal, don’t we? Rachel, let’s begin our feast. You boys better hope we leave some for you!”

The girls stomped and giggled their way to the open field where we currently kept the majority of our cows. A relative handful of their incredibly long strides brought them to their purpose. They kneeled on the ground and each woman started picking up all the cows they could. Not wanting to worry about carrying me, Rachel set me down. Hoping to obtain my own energy, I grew to two hundred and fifty feet. I sprinted away from the overwhelming giantesses with the aim to eat my fill of animals before they could get to them.

Our all-out gorging lasted beyond the dawn. Many of the larger fields and buildings that kept more livestock were emptied of our valuable occupants. I never burped so often in my life. I met several of our human workers early on when I opened up the first building I came across. I figured our workers deserved a chance at eventually proving themselves subservient to the Titan cause, so I told them to collect in my room or risk becoming part of our banquet. They used their radios to spread the message to the rest of the night crew.

I saw the silhouettes of my bigger family early in the morning. I went up to the field they occupied with a stomach that was almost too full. My acids as a giant should have been strong enough to dissolve steel in a few minutes, so the fact that I still felt the final thuds of dozens of little animals inside me suggested that they stood on the gory leftovers of their earlier consumed brethren. Mom and Rachel were sitting down, their legs outstretched in front of them. I assumed their very next pang of hunger would allow them to finish off the fields and buildings farther north.

As I walked up to them, the two women leaned into each other and began kissing. Kneeling by their gigantic bare feet were Alex and Dad. My brother was massaging Rachel’s foot while Dad was working on his wife’s. The male giants looked to have gained some height as well, though nothing drastic. My sixth sense told me I could match or surpass them if I desired, but I did not know by how much or for how long I could hold such a size. The timing also felt wrong. If I was going to expend my energy, it was going to be because I knew it was going to be worthwhile.

I put my hands on Rachel’s right sole. She scrunched her toes in response. Her foot faintly secreted the natural fragrance of freshly cut grass, a dash of rich soil, and saltiness. I looked toward Alex to see him lining his dick up between his older sister’s big and second toes. He humped her foot without Rachel taking much notice. She was engaged with Mom’s lips, both pairs. Her kneading hand had slunk down to Mom’s pussy. Slowly, her fingers amassed Jennifer’s pre-cum and idly slathered it over her labia and clit.

Well after my brother spewed her toes with his seed, my sister and mother were locked in their languid foreplay.

Warmed up enough, Mom said, “I want your tongue in my cunt, sweetheart.”

“I bet I can get a lot more of my tongue in you if you shrink a little for me,” replied Rachel.

“It’s like you read my mind.”

Mom shrank until she was all the way back to her original size. Now overpowered by her daughter, she could not stop Rachel’s tongue from going for her tits first. She coated her entire chest in saliva before taking an entire boob in her mouth. Mom’s chuckle transitioned into a moan as Rachel licked and sucked for a few moments. Only after she tasted both breasts did Rachel move down to the main course.

My sister’s salacious lips kissed Jennifer’s snatch all at once. I overheard the light smacking that came from the contact. A weighty tongue darted out of its den to insert it into another hole. Mom’s whole body shuddered. Offering yet more pleasure was her husband going up to kiss her and feel up tits wet from his daughter’s spit. I was so engrossed by the sight that I didn’t notice Rachel’s hand coming for me.

As I was tenderly trapped in her grip, she said, “My tongue is a bit too big to go all the way in Mom, so be a good toy for your mommy.”

Getting the message, I shrank. As soon as I became the wanted size, Rachel popped me in her mouth. I did not stay in her for long, for she used her tongue’s tip to push me in our mother’s red-hot cunt. With her tongue taking care of Jennifer’s front half, I worked on the back half. The sheer amount of stimulation hastily drove my mother crazy. Her hips kept bucking against the tongue and her convulsing pussy walls never got so wild so fast before.

Normally, being so deep inside meant an orgasm wasn’t quite enough to spill me out of a giantess, but this one was accompanied by my sister sucking out Mom’s juices. I was thus pulled and slurped into my sister’s mouth. I grew while in there so that I could get the strength to rub my dick on her tongue until I came. My sister ultimately dumped me between the heaven of Mom’s bountiful tits.

“Look how cute my little family is!” declared Rachel. “I bet y’all look even cuter if you were smaller.”

To check to see if her assertion was true, the colossal young woman took up more of the horizon and sky.

“Focus on the sun, Rach!” I said. “It can give you more energy!”

With her eyes closed, I could not be certain that she took my advice seriously. In any case, her recently gained energy surely assisted in making her mind-bogglingly large. She was on her knees, yet our six hundred foot tall father looked smaller than a toddler by the time she stopped expanding. She had to be over half a mile tall now.

After opening her eyes, she said, “Holy shit! I’m bigger than I expected.” Her voice alone juddered the ground. Ravening eyes sized everyone up. “Alex! You look good.”

A hand that could crush a plane lifted a giant like a doll. If I was standing, I would have fallen on my ass when my twin fell back on hers. Her legs spread to enclose her family and reveal pussy lips glistening from the arousal gained from eating our mother out. Without ceremony, the godly sister inserted her brother’s strong legs in her cunt. Knowing we were not delicate, Rachel roughly handled her living dildo. She shoved him in up to his waist and pulled him out at a rapid pace, her fingers wrapped around Alex’s head and torso.

In the meantime, Dad settling himself in front of Mom partly blocked a good view of what my sister was up to. For the first time since their early years together, Frank was bigger than his wife. His head plowed right into her left breast, his mouth engulfing her nipple. Due to my proximity, I heard him slobbering all over it. His teeth tugged at the nub while he used his fingers to do the same to the other. His nipple play rocked her tits, which rocked me in turn. I rolled to my side to let the roiling mammaries rub against my cock and backside.

I got close to cumming, but Frank stopped stirring the breasts so much when he drove his stalwart pole in Mom’s snatch. Craving my interrupted release, I crawled out of my mother’s tits and moved toward her head. I also grew, as I needed to be bigger for what I had in mind. I let my legs straddle her neck, then I stood up when my feet touched the ground. I then leaned over so that my upper body lied over Mom’s face. Easily understanding what I desired of her, Jennifer opened her mouth so she could take in my throbbing dick and swollen balls.

There was so much damn sex in the air with my sister treating our brother like a dildo, an assertive husband pushing his wife’s legs up to plow her deeper, and a mother sucking off her son’s cock at the same time. As my mother swallowed the cum I jetted into the back of her mouth, the thunderclaps of Rachel’s wailing orgasm overcame all else. By comparison, our father’s grunting climax sounded as though a porn video was put at a volume barely above mute. Cooling off, Rachel picked Alex up to her mouth so she could lick her own gluey sap and get him to cum. With those goals accomplished, she set him down by the rest of her family.

Some moments of rosy reflection later, Rachel said, “I want to go for a swim so bad, but I don’t think any lake nearby can hold me, and I don’t want to shrink. How far is the ocean from here?”

“A little less than a thousand miles west, baby girl,” answered Frank.

“I’d guess you can walk there in an hour,” I said.

Mom sat up. “That will probably force the humans to take action. I doubt you can walk all the way to the sea without stepping on some of them.”

“Or eat some,” said Alex.

“Exactly. We could force them to take drastic measures. I think we should gather a bit more energy and master our size changing ability for a while longer. For one thing, Ryan, did you say something about the sun earlier?”

“Oh, yeah. At least for me, I think I can absorb some energy straight from the sunlight. It’s not a lot, but it helps stabilize my growth spurts.”

“See, we all need to figure out whether we can do this as well. If the sun alone can bring us a few thousand feet on its own, we won’t need to waste so much energy from our food.”

Mom was right. Therefore, we all shrank to more manageable heights and decided to use the next few hours to train in converting sunlight to size.

It was obvious early on that I was the best at taking advantage of the sun’s donation. Without implementing any internal energy at all, I could steadily keep growing until I broke my concentration, which happened about every minute. Each of those stints gave me fifty feet or so. The rest of my family added about half that in the same amount of time. It was a slow way to grow, but I foresaw that the sun would be our main source of growth when we were too big for humans to offer much energy.

Near noon, I remembered that I was supposed to meet with the doctor. I invited the others to come meet the human who unlocked our potential. With all of us around four hundred feet tall, we went to the visitors center. We boys lagged behind the pert girls to specifically gawk at their swaying asses. Since they knew of our overt intentions, they embellished their enticing movements for us. I was disappointed to see our short journey end.

The doctor came up to the top floor of the visitor’s tower within a few minutes of arriving. We had much to discuss, so we took him to our home. He and I had recently discussed hypotheticals concerning what to do once the Titan gene proved to be all it promised to be, but now we needed to go beyond hypotheticals. It was time to begin the process of making the world our own.

With the humans always keeping mechanical eyes on us, the word of our ability to grow soon got out. It wouldn’t be long before the antagonistic humans called for militaristic measures to be placed upon us. The good doctor and many of our workers already left to begin organizing our human supporters. This meant getting into contact with the cult-like organizations that the internet claimed several million people were a part of worldwide. They did not officially state that they would mindlessly follow our orders, but it was kind of implied. These cults frequently sent my family food of the nonhuman kind, but we had not thought about them much otherwise.

The long-term plan for the cultists was for them to become the world’s new human leaders once my family took care of major resisters. A reward for believing in us before we subjugated the others. For the short-term, we just really needed them out of the way so we didn’t accidentally crush or eat them whenever our romping rampage started.

There was no need to go running amok just yet, so I was with Rachel on her bed. The last few days of growing took a lot out of the family, so everyone was currently resting bodies sore from our distinctive workout. I kept my size equal to Rachel’s own. This allowed me to spoon her like a true lover. Despite what my dick snuggled in the crack of her splendid booty suggested, my mind was not interested in fucking her. I was merely exceptionally happy to hold my giantess twin in my arms, watching as she peacefully drifted off to sleep.