"Hmm." I looked at the dirt covering my index finger in curiosity.
Unlike Rimuru, who casually altered his entire body on a molecular level in order to utilize Infinite Shapeshifting, genuinely becoming something of a human facsimile, after many, many simulations with Thoth's prior Curiosity incarnation, I learned that nothing I could create with Infinite Shapeshifting was half as adaptable or durable as my original slime cells. As such, when mimicking human, I'd utilize my own original slime cells, then smash them together until they were denser than Oricalcum before subtly altering the weight with Horus.
Originally, I'd mimicked animal muscles, but after learning more about physics, I'd realized that, since every single one of my cells technically existed independent of the others, and I didn't particularly need muscles, the best way to increase speed and power was to simply turn my entire body into one big mass, as dense as possible, so that all of the power was distributed perfectly evenly.
Since I didn't like to make alterations to the cells, atoms, and molecules that made up my physical structure, the main way I utilized in order to affect my skin color was subtly changing my vibrational frequency at the atomic level. That changed the way my cells interacted with the light, altering colors well enough to suit my needs.
As such, when I'd changed my finger's color to the same as the dirt, then changed it back, part of me had expected the dirt's vibrational frequency to be affected, too.
But apparently, Horus only subconsciously affected my actual cells. In order to affect anything else with it, I actually needed to consciously choose to do so. But it still did affect the magicules that'd passed through my internal stores.
How interesting. I was surprised that I'd never noticed that before.
This time, still withholding Horus, I directed the weird, evolved magicules to completely cover the dirt around my finger, while I shifted my finger's color again. I didn't know much about these evolved magicules, but normal magicules tended to have a fairly strange way of interacting with regular matter.
While simply covering something with magicules and hoping wouldn't be enough to force the right kind of magic to happen, with regular magicules, I wondered if these evolved ones could do so, even without influencing them with Horus.
The answer: Nope. When I pulled the evolved magicules back into my skin, my finger was squeaky clean. They'd utterly destroyed the dirt on an atomic level, despite the fact that I'd only had them surround the dirt rather than infuse. Honestly, it was the obvious result. Still, though, I was satisfied with that. Data was data. The simple feeling of an experiment being recorded into Mnemosyne's archives always felt exhilarating, even if I was just doing it to pass the time.
"I'm soo bored! How are you not?! Help me! Teach me your de-bored-ifying ways, Risa!" Milim complained silently through the wall, connecting to me via Thought Communication.
Noticing Milim's Thought Communication, Frey hit her over the head with a rolled up piece of paper, but Milim's response was just a bunch of really, really bored emotions slamming into my head via Thought Communications.
But my own thoughts were already whirling beyond that.
Connect to me… via Thought Communication…?
The realization, the theory, hit me like a freight train. Immediately, I began running Thoth's analysis functions in overdrive, checking it over and over again, doing calculations and re-analyzing my own soul and available skills several hundred times in the span of an instant.
Yeah, it's possible.
I realized it with a start. My outlandish idea was completely possible. Even easy, in theory. Almost as if this was what the skills had been made for in the first place.
Slowly, carefully, I used Nephthys as the base of my endeavor. While it made more sense from a logical perspective to use Horus first, but Nephthys was more stable and adaptable when it came to 'soul' situations. Even though using it forced one to make some sort of sacrifice, it was literally a skill designed to give power in exchange for promises.
The promise had to have something to do with what you were going to utilize the power for, and there'd be severe backlash if the promise was broken, but the skill could theoretically do nearly as much as Horus, if used correctly.
The promise I started with was simple. Not harming Milim. Simple and easy for me, which meant that it didn't grant as much energy as someone on my level who disliked Milim would get for a promise like that, but since it involved one of the strongest beings on the planet, someone who could easily slaughter even Ultimate-level beings like Big Bro Rimuru and I were she to really try, according to my simulations with Thoth, it still granted me a good structure of power to build the rest of the ability on.
I sculpted and added to that base by adding clauses and small points to the promise, turning it into a Pact Contract. Then, I let Isis read through it and alter it a bit, to ensure that it didn't end up hindering us somehow, if necessary. Once a contract became complicated enough, it was possible to find loopholes for nearly everything, while still having a fairly good power base. This particular Pact Contract wasn't that complicated. Milim and I would still be unable to genuinely attempt to permanently kill each other at the soul level, for example, without losing around 80-90% of our power. I made that one especially strict, because I figured that, if it did happen, the best result possible would be for us to end up so weak that we became physically unable to follow through, anyway. We also couldn't override each other's wills without permission, unless special circumstances applied.
The contract would get us close enough that our subordinates would be able to stop us, with some serious effort.
Then, once the contract was perfect, I used Horus to slightly change its nature, allowing the Pact Contract itself to subtly merge with Aether's 'Soul Connection' power.
And finally, through Thought Communication, I sent the contract to Milim directly.
With Horus subtly altering the way both skills worked, the Nephthys Pact would instantly create a stable Soul Connection upon acceptance, bringing Milim directly into Aether's influence. It'd create a connection that couldn't be blocked or used against us, allowing us to communicate as clearly and precisely as Rimuru, Veldora, and I could.
"What the-" Milim was confused, but only for a moment. The terms of the Pact Contract were clear, the effects, how we could use the resulting Soul Corridor, Milim was one of the most well-learned people on the planet, even though she didn't like to act like it. She grasped it instantly, and accepted the contract without reservation a moment later.
A direct soul-connection to Aether was way too good a deal to pass up on. Especially with that Nephthys Pact making it impossible for either side to overextend their authority without permission. On top of that, either side could break the connection at any time, with sheer willpower.
But I'd made one miscalculation.
Upon taking effect, the Pact instantly snapped, and the connection failed. Milim's spirit was simply way too strong. Interaction with the deep part of her soul was enough to snap Horus's influence like rotted wood.
Still, since the contract had simply lost effect, rather than being broken, there wasn't a punishment. So, Milim and I reworked the contract and tried again.
And again.
It was the tenth reworking of the contract that finally worked. As soon as Aether finally took effect inside her, the Soul Corridor solidified, held together by Aether's Unlimited Imprisonment base. Horus's effect faded, unnecessary now. The Pact Contract took full effect, regulating the soul corridor between Milim and the rest of Tempest through Aether as its own domain.
Like a switch flipped, it was all or nothing. The connection was complete.