[*ding!* [Anatomical Drawing] leveled up! 29 -> 30]

Simply sketching and resizing all my organs, muscles, joints, bones, etc., to fit inside my body was merely the first step. Nothing played nicely with each other, and it was my job to figure out what compromises were needed to get everything running smoothly.

Things went from as complicated as blood pH, to as mundane as ‘what temperature did my organs want to be at’. I had a mix of warm-blooded and cold-blooded organs, and I needed to do things like check if the excess heat from the warm-blooded parts would destabilize the enzymes and reactions that the organs used to operating at a lower temperature would try to perform.

The unicorn bone marrow needed to produce a slightly different type of blood cell. My small intestine needed to properly process titanium.

My liver needed to un-fuck titanium digested by my stomach.

My kidney got significant attention, or rather, waste management.

Life was full of risks. There were dozens, hundreds, thousands of different ways I could die. My modifications were going to make me faster, stronger–better. It was the name of the class after all. I firmly believed that my changes would help me survive in hundreds more places that I wouldn’t normally, while opening up a few niche scenarios where I’d be in more trouble than before.

Close seven hundred holes. Open three. It was worth it to me. The ability to improve myself in nearly every physical way, from being faster, stronger, quicker, improving my reflexes, letting myself eat anything, giving myself hours of air, giving myself not one but two new senses, extra brains to dodge my headshot weakness, freaking armor under my skin - I got all that, for a vulnerability to getting cut off from the System for days on end.

Not even mana! The Arcanite I was designing into my skeleton would handle that. It mitigated the threat of a powerful curse eating all of my mana regeneration. While curses could zero out my regeneration, they only rarely hit a target’s mana pool, and even then my ‘use mana to cast’ took priority over a curses’s ‘drain current pool’. Assuming both were instantaneous.

No, it’d have to be a massively powerful Canceler who wanted me dead, and like.

If they were that much stronger than me, and had me in their power, and wanted me dead? I was dead.

The other weakness was getting blasted to another world, one without a System, and I considered that prospect to be vanishingly unlikely. I did make a second tiny hollow in my body, and aimed to put in a pendant of the five gods, wrought out of cold iron. It might not work the way I imagined it would, but either way I was determined.

No more fae shenanigans. I wasn’t going to let them screw with my life again.

I considered the trade off to be worth it.

One aspect I hadn’t thought all the way through - my vitality helped extend how long I could be without my healing magic. Instead of days at my baseline, I was probably weeks before the build up started to cause significant issues.

That was assuming I got my mana cut off, and I wasn’t cut off from the System entirely. Only way I knew of that happening was getting yoinked back to the Fae realm, and I was taking permanent precautions against that happening again.

That was my kidney baseline, and it assumed my current design did nothing. I wanted to make modifications to expand it further, but it was at the bottom of my list.

Other math was less fun. My hearts were a big issue.

If I tried to run them in parallel, I needed two full designs of arteries and veins. Not the end of the world, since I could ‘layer’ them next to each other, while having capillaries constantly exchanging blood between the two to maintain equilibrium. The downside was a spacing one - everything was just so cramped already! I wanted to run my arteries and veins as close to my bones as possible, which required finagling at my joints, and if one heart got taken out, I’d ‘lose’ most of that circulatory system. Lung oxygen uptake was also tricky. That was the main sticking point of having them in sequence, and each capillary system would need to ‘dance’ around each other, dramatically cutting my total oxygen uptake. Half my air-related efforts would get shredded. My body would also adapt over time to having both systems ‘live’, and at the end of the day, it started to look like I’d be doubling my weak points while decreasing performance.

If I ran them in sequence, I encountered an entirely new set of problems, namely around the lungs, and secondarily on blood flow. Two hearts pumping was a lot, while only one heart pumping wouldn’t be enough.

It was a mess, and none of my calculations were coming out with a happy face. I started a new notebook for questions I’d ask Marcelle.

I wanted to do them in one big go, instead of constantly wandering over there and seeing if she was in her office.

Amino acids were next.

They were much easier than I’d feared. Initially, I’d been concerned that some of the species I was mixing and matching from would use a different set of amino acids, but no. Out of the thousands and thousands of potential amino acids that existed, all life consisted of the same 20.

My essential amino acids - the ones my body couldn’t produce - had changed around a bit. It called for the most minor shift in my diet, and I’d loop back around to them later. With a bit of work, I could make all amino acids nonessential.

Amino acids set, I had the raw materials to build any and all proteins my body needed. The trick was now to ensure my body could produce those proteins. The arachnid spider-silk tendons and ligaments, for example, relied on a substance produced in their ampullate gland.

I could potentially make it on-site in the tendons themselves, but that would require dissecting exactly how the ampullate gland worked, and finding out why it was being produced in a specialized organ and not on-site.

Humans didn’t have an ampullate gland. Hells, I couldn’t even find a comparative structure!

Fortunately, they could be tiny, and I had evicted my spleen earlier in the design process.

That was simply the start of my protein woes, and that was with all the amino acids present and accounted for!

Then there was every other nutrient required. I got two organs in before taking a step back, and listing out the requirements for every single part of my body.

Then it was off to the stomach and digestive tract!

Fundamentally, I’d still need to eat all the nutrients my body required. I wasn’t handling exotics, like poison or venom, so I didn’t need to eat special beetles for venom production or anything like that. A benefit to keeping things simple!

Of course, some creatures generated the toxin wholesale, and didn’t need a specialized diet, and…

I was keeping it simple.

Instead, I needed to tackle the digestive tract, specifically the stomach and small intestine.

The small intestine got a pass. I’d picked pig specifically because it could absorb everything, and absorb it well. If there was something it couldn’t do, well, I’d simply replace it with a small intestine that could. That was its only job.

The stomach was trickier. Specifically, vitamin K1 was giving me a hard time, while K2 was properly passed through. Why on Pallos K1 wouldn’t work while K2 did, I’d never know, but the two were practically interchangeable.

Bloody hell this was a pain.

Item after item, cross-compatibility after cross-compatibility. Weird, random problems.

Like, how did I handle my rainbow serpent skin layer when it shed? It would shed between two layers of skin, would I peel off my entire epidermis every time it wanted to shed?

The trick happened to be approaching it sideways. Snakes shed their skin when they grew, and they were almost always growing. Turning off the growth mechanism stopped the shedding problem entirely…

… unless I ended up overshooting when using [The Stars Never Fade]. I was happy with Immortality, but boy was it screwing with my biomancy designs.

I went back to fiddling with the snake skin growth mechanism. Instead of entirely disabling it, I had it trigger only when the pituitary was sending out the ‘grow grow grow’ chemicals. It didn’t stop the ‘shed-explode in a gory mess and temporarily become a snake lady’ problem, but fuck it.

It wouldn’t kill me, and the problem was niche enough that I wasn’t worried about it.

Lifespan calculations. How long did each part last? When did I need to get worried enough about my body to use [The Stars Never Fade]? I knew how long a human lived, but what was the average lifespan of a tiger?

Correction.

What was the average lifespan of a tiger, after adjusting for their typical vitality? Reference books gave a typical lifespan, but there was no way of knowing what the typical vitality, and therefore lifespan multiplier, of a tiger was.

The same went for every single body part I was using, with an added twist.

I was looking at frog’s third eyelids for my design, for example. Frogs tended to have a short lifespan. But would their third eyelid degrade at the same rate, or was it something like their little froggy heart giving out after just a few years? Or were the numbers utterly skewed by the sheer number of creatures in the world who found frogs delicious?

There wasn’t an answer to my question, not in any reference book I could find.

Design after design. Compromises and solutions. Clever fixes and janky hacks. One issue was solved, and it broke three fixes. I’d feel pleased as I finally wrapped up the nerves, only for my electrical sense to turn into a dumpster fire.

But.

One by one.

Minute by minute, hour by hour, day by day.

I was getting there. My list of active issues had more items taken off than added on.

I was getting there.

“Evening, love.” I dragged myself in through our dorm door, Iona studiously going over her books.

Not math, thank goodness.

“Here.” Iona grabbed a mug from the coffee table and held it out to me. Bless my girlfriend. I never asked for it, yet she unfailingly always had a cup or a snack or a treat waiting for me after a long day of working.

“Bbbrrrrrrrrrrrrrpt!” Auri attempted to dive-bomb the exposed mug. I flickered out [Mantle], protecting my drink.

Auri faceplanted right into my shield.

“Thanks, you’re the best.” I grabbed the drink from Iona, sitting down next to her and leaning in.

“Rough day?” She asked as I sipped the mango juice.

“Oh yeah. Massage?” I gave Iona my best puppy dog eyes.

Drat. That’s what I should’ve done. Puppy dog eyes, not tiger eyes.

She leaned back and patted her lap, and I splayed across her, carefully keeping my mug upright.

“You’re the only one I know who can get sore sitting in a chair all day.” She teased me as her fingers sank into my sore butt.

“Mmmmm. You know it.” I said.

“Do you want to talk about it, or have a break?” Iona said.

“Brrrpt?”

“When I’m done with it, Auri. Talk. Somewhat. I’m almost done. Tomorrow I’m going to Marcelle, and I’m going to ask her my question list.” I took another deep drink of my juice.

“BRPT!”

“Fine, here.” I extended out my nearly finished mug, Auri diving beak-first into it.

“Oh! Oh! Is my question going to be on there?” Iona asked.

I was going to lose all credibility with Marcelle when I asked Iona’s question. Her gentle massaging fingers, and the fresh mug of mango juice she had waiting for me made it all worth it.

“Yup. I’m not messing with your brain if that’s the answer though.” I said.

“Not even for thirty minute-”

“Nope.” I interrupted, knowing the rest.

Iona clicked her tongue.

“Drat. Hey, do you want me to redo your diagrams and drawings for you?”

“Yeah! Please, that would be amazing.”

“Two days from now I’ve got the day free. It’s a date!” Iona said.

I gratefully kissed her.

“Brrrrrrrrrrrrrrrrrppppppppppt.” Auri made a disgusted noise at our antics.

“I had an idea about Fenrir.” I sighed with relief as Iona’s wandering fingers undid a knot.

“What’s that?” Iona asked.

“I should make the whole thing into a mystery, and give him a ‘case’ to ‘solve’. Have some sort of, I dunno, evil blood sucking lair or something. He’ll happily give up some blood if it’s for his ‘case’.”

Iona laughed and spanked my butt.

“Whoo!” I jerked up, my mug jolted up, and a juice-soaked Auri went flying across the room.

“BbbbbbbbbbbbbbrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrpppppppppppppTTTT!!!” She complained as she let herself get catapulted across the room.

She could easily open her wings and catch herself, but she had a sense of humor.

“Fenrir would totally go for that! Let’s see, first we need a victim…” I straightened up on the sofa as Iona animatedly described the perfect “mystery” for Fenrir.