Back at the base Erik was in the genetics module thinking of a solution to improve the blood flow and blood generation, the easy solution would be a blood bag inside the body but that would overwork his kidneys, and generation blood too quickly would require more bone marrow, he started creating the 3D model and in the end, he decided to add small enlargements in his veins to be able to hold more blood inside and deal with changes in pressure better, the higher amount of blood would also allow his body's bloodstream and also tissues by increasing the concentration of myoglobin, the oxygen storage protein in muscle to hold much more oxygen, with those 2 changes he would be able to hold his breath way more if he needed too.

He then enlarged the kidneys a bit to deal with filtering more blood.

Another organ susceptible to compression damage is the lungs, so he reinforces the peripheral airways, and that allows the lungs to collapse underwater without tearing or exploding, that also makes it safer to dive without suffering from narcosis as it lowers the gas exchange with the blood, that would also deal with decompression sickness, while his artificial gills supplies oxygen to his bloodstream and eliminates CO2, it would need good water flow for his gills to work though so he also plans to use the flow from speed-enhancing turbines on his back to increase efficiency, it could also be run at low speed in stale waters just to oxygenate his blood, his increased blood capacity would also take more time to fully oxygenate his blood but he would hold out longer without breathing.

There were also other problems like gas inside the organs and other body parts and tissues but the power armor would deal with that, he then also added a stronger heart to circulate more blood and thicker bones to regenerate blood faster.

As he was done with the life-threatening problems he started thinking of what fun and handy things to also add. The good thing about having more blood is that he would be able to support a bigger dick so he increased its size by one third and almost doubled the girth, then he added some muscle tissue at the base of his dick, so he could have voluntary control over when his veins constricted, allowing him to maintain the erection for as long as he wanted.

Then since he was at it he gave himself bigger balls to feed Inky more baby butter human DNA, and a bigger prostate to cum more, in this world where you could become what you ate it was useful, it also felt amazing, he grinned imagining Inky’s reaction, and as a finisher, he increased his body’s number of muscle fibers a bit, that would increase his strength and agility considerably.

The simulation was blinking red by now, with warnings saying the change was deadly and not permitted, but he overrode the security parameters and got inside a pod, starting the process, he expected the ARK system would allow him to mutate successfully.

As he was floating on the liquid, multiple needles injected the just made mutagens all over his body, and life support systems connected themselves to his body with tubes as it was determined as a huge change, he had also selected the injection of paralysis anesthesia so he would try to do anything stupid, but he still felt it through his veins, it was like fire seeping all over the inside of his body even inside his bones, and then cane an unbearable itch, his entire skeleton and internal organs itched, he released a muffled scream in the breathing mask as he passed out due to the sensory overload.

--- 1 day later ---

Inky was worried looking for Erik all around the base and couldn't find him anywhere, he had been gone for an entire day without telling her and they hadn't even eaten together as she had to make for herself some fried eggs and sashimi.

She started looking module by module, finally finding him floating inside one of the tanks and gasped, his face and body looked hideous as veins pumped bulging all over his skin and he was covered in bumps that were moving under his skin, she was horrified and hit her fist against the glass but it did nothing, as she was about to go look for a weapon to take him out she saw him open his eyes and she paused.

Erik opened his eyes feeling the worst he ever had, but he knew it was the result of genetic modifications clashing, but he wasn't in danger yet, he saw Inky about to go and panicked though, if she took him out the change would stop there leaving him like this and deformed as the liquid and tubes also infused nutrients in his body. He hastily forced his deformed hand to move and typed on the screen, a virtual voice replying outside "Inky, it's okay, just wait for it to finish".

She looked at him worriedly, then at his body, and slowly nodded, going away.

Erik relaxed a bit, but not much though as he still felt like snakes were crawling under his skin and rats were feasting on his bones and organs. He typed the scan on the screen and a ring-like device scanned the tube and his body, showing his situation on the screen, apparently the vein enlargement was clashing with the heart and muscle enlargement the most, like bugs in the lines of code he rapidly selected the manual gene coding function and added "awaits" to the other functions so they waited for the last one to change before executing, it was a fast change but would work, he quickly executed it and felt the needles inject mutagens again, his change started stabilizing as the muscles were selected first, then would be the veins and then the heart and bones, finishing with the kidneys and lungs all the life-threatening changes, then the other changes like his member growing from 9 inches(22,86cm) to 12 inches (30,48cm) in length, and from 5 to 8cm in girth (~3,2 inches) would follow, the itch and movement were still making him crazy though as all the clashing had also given him a lot of pain.

Unlawfully taken from Royal Road, this story should be reported if seen on Amazon.

He selected the anesthetics options on the screen and selected the high tier and clicked on start, a needle quickly injected him and he passed out.

--- 5 days later ---

Inky was feeling bored these past days just by herself on the base, but she could see Erik's body was looking good now, tempting good in some places and relaxed, hoping he came out quickly and went to check on him like she did for the past 5 days, and was elated as she saw his eyes open and the liquid draining.

Erik woke up after 5 days of chemical-induced coma, his body no longer itched, and he felt great, clenching his hands as his feet lightly touched the cold floor of the tank, the liquid drained and the life support systems started disconnecting from his body, once done he took the mask off and stepped out of the tank, putting on the translation device as Inky closed in excitedly.

Inky: "let me see! let me see!"

Erik just smiled and remained still, letting her touch him all over his body. She first touched his more defined chest muscles, tracing them with her hands, going down from his chest and to his naked nether region as she exclaimed, then looked up to see Erik's smiling face.

Erik: "wanna lick it?"

Inky smiled too as her fins moved happily and didn't answer, instead just lowering herself in front of him as she stroked his new member with glee and then took his tip into her mouth, giving him a blowjob and soon deepthroating it down her slimy throat, feeling Erik's dick enlarging inside her as she went faster. She seemed to be enjoying herself as her dick was also getting hard as she was stroking her half-mast shaft while also fingering her already dripping wet pussy, her head bobbing as she took him deeper and deeper, finally touching his balls with her chin as her eyes rolled back.

Erik was delighted to see Inky enjoying herself, he couldn't help but moan as he felt his now full mast 12 inches (30,48cm) going down her slimy throat, the tightness and strong suction feeling amazing. Erik smiled while looking into Inky's eyes and grabbed her head, seeing her eyes dilate as she started masturbating faster, Erik smiled wickedly as he had an idea.

Erik: "guess I can try being rougher today..."

Inky didn't know what he meant but she wasn't listening by now and only became more delighted as Erik's hips started rocking back and forth, his dick going up and down her throat with a visible bulge, she was about to cum herself by now as she felt Erik speeding up as his big plump balls slapped against her chin again and again. She finally reached climax and came hard, her sperm staining the floor and her pussy juices squirting, then she felt Erik grab her head and push deep down her throat as his dick started pumping load after load of sperm down her throat, at least 10 times the amount he normally did, and she loved it, it came down her throat and to her stomach.

Erik slowly took his dick out to her mouth and left it there as she cleaned his dick, sucking the remaining cum out, taking his dick out with a pop. Then as she looked lustfully at him, he tried something, concentrating on the base of his dick, it enlarged slightly, pointing up, the bulge of muscle constricting his veins, keeping the blood flowing inside and his dick at full mast for as long as he wanted.

Seeing his hard dick she almost started salivating and quickly turned herself, spreading her dripping wet pussy, and looking back at him.

Inky: "quick! quick! fuck me~"

The voice coming out of the translator was slightly stiff but it excited him nonetheless, he lined up his cock to her entrance and penetrated all the way to her cervix in one go, the extra girth making Inky squeal in delight, he wasn't fully in but left it there a second to let her body adapt and then started to slowly fuck her, getting a bit deeper with every thrust as his dick nocked on her entrance, her cervix sucking on his tip. After working on it for some minutes as she moaned, his dick finally pierced through and inside her egg sack. Erik moaned loudly as he loved that slimy all-encompassing feeling all around his dick like if dozens of tongues were licking his member at the same time accompanied by the tightness, she was also moaning loudly as he finally went balls deep inside her, their hips colliding and slapping together as Inky orgasmed and sprayed the floor with her eggs as she lost strength from the deep fuck, Erik supported her and continued hammering into her, finally cumming a flood inside, pumping lots of his warm baby butter inside her and felt her pussy contract and orgasm again.

They kept at it until her belly was bulging with cum, after having changed positions dozens of times already, cum dripping out of her cunt every time he thrusted inside.

After all that humping, Erik was panting, feeling exhausted, and laid on the ground, his dick still hard and pointing up like a flag pole. Inky swiftly climbed on top of him and impaled herself on his member with a smile, riding his dick as cum continued to drip down out of her pussy from all the earlier action. They continued like that with Erik dry cumming until Inky came for the last time, almost no more eggs inside her egg sack as she collapsed on top of his chest with a satisfied smile and standing fins while still impaled by his dick. She looked up at him while tracing his chest muscles with her finger.

Feeling that it was finally enough Erik relaxed the muscle on his very shore dick, the blood flowing out as his dick went limp and popped out of Inky, his cum dripping out of her like an open faucet, if Inky's pussy wasn't so slimy and wet his dick would have caught on fire by now, he had dry cummed inside her lots of times, thankfully his higher oxygen content on his blood also gave him more stamina, he was too tired by now though. He was thinking of taking a nap right there, as he caressed Inky's back when he looked around and noticed something really important he had forgotten and facepalmed 'we are still inside the module..., dammit! this will take forever to clean...' he really should clean it right now but was too tired and fell asleep right there.