Mob Devil's Guide To Surviving DxD

*BOOM*

A massive explosion.

My body was a ejected upwards out at speeds of over 150 kilometers per hour. But just before full crashing on the ground I managed to brace myself.

"ARGGGH!!"

The pain was only slightly bearable. but the fifteen-year-old boy managed to pull through it like a champ. This is obviously not the first time something like this has happened.

"Shit. Shit. Shit. Damn, I messed up in the calculations. "

What am i doing right now? What exactly is this situation? The answer is simple. Magic experimentation.

"Damn, good thing i stopped doing these experiments in the house. Mom would have f.u.c.k.i.n.g killed me if I tried this back there"

"sigh, going to have to rebuild the lab... again"

"Another failure. Damn, what wrong? is it really impossible to imitate the boosted gears doubling effect using demonic power?

Welp.. if anything, I developed a decent suicide bombing technique."

-------

To summarize devil magic, it is the power of imagination. You can achieve anything with this power as long as you have the power to supply it. Then what makes 72 pillars special compared to reincarnate devil? It is an instinct. Any devil can use the power of the pillar family, but pillar family has a greater advantage. For the pillars family, casting a spell that their bloodline is based on is as simple as breathing. A Phenex could change to their fire form and regenerate easily. A Bael could apply the concept of Destruction to any of their magic if they supply enough power even without enough control. A Sitri can master any water-based spell without much effort.

But like all things in this world, there's a catch. Everything has their strong and weak point.

Doing devil magic is both easy and hard. Easy that you only need your imagination and power to do it, but hard because you need to fully concentrate on the spell as long as you cast the spell. Imagine that you want to create fireball to burn your enemy, you need all your focus to cast the devil spell, but just when you about to cast it, Megumin comes and screaming "EXPLOSION" right beside your ear. The result of your spell is that instead of fireball, it becomes a mighty explosion worth of power of destruction that drains all your demonic power if your spell works correctly. If not then I will bury whatever left of your body.

Thankfully, the first abilities I developed was Thought Acceleration. With the help of Thought Acceleration, I have all the time in the world to concentrating my imagination. As long as the enemy I faced is not faster than my acceleration of thought, I could cast any spells I know.

The second ability, further takes The Accelerated thought process, and segments it like a computer would.

Thought - Memory Partition is an ability used by the superior alchemists of Atlas. Paired with Thought Acceleration, the very proof that one is an Atlas alchemist, it is the ability to partition their thoughts to form multiple independent thought processes. While normal people can only have a single "room" in their brain and focus on one thought, partitioning adds partitions to the one room to create multiple rooms. The prerequisite for the superior alchemists of Atlas is at least three rooms, while five is on the level of a genius. Sion Eltnam Atlasia can manage seven partitions, while a past Academy Director had achieved eight partitions.

It is different than having multiple independent machines in their heads because, while there are multiple processes, they work toward one goal. They manage different problem sets, but work together to generate one overall solution. While machines can calculate on the same level, nothing else compares when used for problem solving. The limit of an average alchemist is one thought into multiple rooms, but superior alchemists can perform first−order tetration of their thought into rooms.

In addition, the rooms are synergistic.

for example, Four partitions allows for 256 thought processes. As they work towards one goal, it does not allow for 256 separate calculations.

Through 15 years of practice, I have managed to achieve 5 partitions. That is about 3125 thought process is all focus on the same goal. This combined with thought acceleration, I am basically a living supercomputer.

With this, i had managed to create spells and abilities in the two digits. soon approaching three digits.

of course, it's not perfect. As I am still human or in this case a devil, it's still possible to get distracted and make miscalculations.

As with this case right here.

A "simple" attempt to try to recreate boost had turned my body into a proverbial bomb.

- Boost gear effect recreation experiment: number 433

- Results: explosive diarrhea.

"Damn... I'm tired today. I'm going home. "

I struggle to get up, looking at my bloody body, i activate a body restoration program.

--Pseudo magic circuit startup...

--Beginning restoration protocol...

--Analyzing affected area...

--Estimated damage degree.... YELLOW.. .

--Ruptured liver... Right lung penetrated...slight brain hemorrhage... ruptured eardrums.. shattered t.e.s.t.i.c.l.e.s...

--[Avalon] starting up... restoration progress:15%....44%....78%...99%...

--Report... GREEN...

The devil is an unconscious shape sifter. Their body will change slowly to their idealized form. This comes in handy because when I was training, my muscle will grow stronger than a human could be with higher density. But muscle isn't the only things that grow. My whole body is slowly becoming more efficient, my bones being denser and stronger, my sensory perception becomes sharper, my demonic power grows bigger. 

This spell I named [Avalon] takes advantage of that. It uses the unconscious shape-shifting ability as a starting point, Then combined with various other effects, i created a restoration program that was only about 1/15th the speed of a phoenix regeneration.

And it's just slightly slower than using Phoenix Tears.

In other words, as long as I'm not killed instantly. I'm not going to die

With that done, I teleport instantly back home to my family's house in the underworld. There, I'm greeted by an unexpected visitor: "You're finally back, Young Master Linnaeus"

Standing at my exit zone was none other than maid of satan sirzechs. The strongest queen, satan yellow, my combat instructor -- Grayfia Lucifuge.

"Sensei? Why are you here? please don't tell me it's another one of those surprise training session"

A request from the Lords?

I focus as this seems to be a serious case. I collect all my thoughts and calculated all possibilities and I quickly came to a conclusion as to why she might be here.

"The next heir of the clan has taken her peerage and seems to have run away from home to the human world."

My conclusion was correct.

"Of course, she's using the pretext that she wants to study in the human world. But we all know why she's going there."

"And my mission?" I replied.

"We want you to enroll into the academy with her to... keep an eye on her."

"We already know that you seem to have a home there, so it shouldn't be a big deal for you."

"First semester starts in six months, prepare yourself"

These next 3 years, let's make my final preparations in this time.

"Oh, by the way. Congratulations on your promotion to mid-class"