There are a lot of ways to raise the dead.
You can pluck their bodies from the grave and tie life energy into their bones, weaving it through their corpse like muscle and tendons until you have a fairly simple puppet.
But such creations can't reason or think for themselves.
The most common solution to this is to anchor a soul into the corpse.
Of course, catching a soul isn't as simple as it sounds. Most souls leave the body at the point of death and there's not enough time to snatch them before they dissipate into the ether, presumably to rejoin the Resurrection Wheel and be reborn.
Some souls, however, have a weight which prevents them from dissipating.
These souls carry on as Restless Spirits, which can take many forms.
Vengeful Spirits are the most common because rage and revenge are powerful motivators. It can light up your spirit with a source of power that can take hundreds of years to slowly fade away.
In the meantime, the ghost will rail furiously at anything and everything.
Anyone who's gone for a pleasant walk through the city park only to step in dog poo left behind by some inconsiderate mook who's been walking their pet will understand how they feel.
The problem with using these souls is that they're inherently unstable. The emotion which powers them frequently consumes their sanity over time and leaves only a single-minded barely-conscious entity. Many are unsuitable for use in an undead host.
Finding a suitable spirit is like looking for the proverbial needle in a haystack.
More impatient necromancers have since worked on ways to strip the spirit of its emotional weight and replace it with a small battery of life energy which would power the spirit's existence.
Unfortunately, it creates an emotionless creature whose responses are clinical and detached. Some necromancers prefer this. I know I would if it weren't for the fact that this was also inefficient as life energy would need to be constantly supplied to the battery.
This was the basic mechanics of creating a vampire.
The vampire sourced its life energy from the blood it consumed.
As you can see, there's pluses and minuses to the many ways one can manipulate a soul for the purposes of necromancy. Especially if the necromancer is not advanced enough, or is too impatient, to consider proper and more efficient methods.
Of course, the absolute worst way to cleanse a spirit of its emotional weight was to siphon it into a Soul Crucible.
Once upon a time, a petty little necromancer called Gerald Kilsyth (the Senior, not the Junior), was frustrated by his efforts to create a large army of zombies who could march in an orderly fashion rather than stumble haphazardly in chaotic mobs.
His aristocratic upbringing refused to accept that his minions couldn't muster the bare minimum of intelligence required to maintain a proper and dignified formation.
So, he researched the anchoring of souls and, after much thought, decided the best thing to do was not just to strip the emotion, but also the personality, of the spirits.
He had come to the conclusion that it wasn't intelligence or emotion that caused small deviations in how the undead responded to his demands. It was their personality.
And if they didn't have one, they should all behave the same way.
This is technically true, of course. However, I'd argue that if the necromancer in question wanted a small army of functionally identical minions, the necromancer should probably look at creating Golems instead.
Kilsyth, though, was stubborn.
And he created a device which sucked in surrounding spirits and then sort of blended them together into a giant ectoplasmic smoothie. He then filtered out what he termed their contaminants and was left with a thin ethereal soup which he could attach to any undead.
The resulting creature had some intelligence, but it was an animal intelligence. Simple and unrefined.
Excellent for marching and burning down small villages before eating the screaming occupants.
And that's about it.
Kilsysth's Soul Crucible ignited a frenzy of debate around the value of reducing a soul to its most basic form. Some necromancers considered it a genius idea and imitated it.
Others thought it was cheating.
I stood at the base of the ziggurat, noticing the fleeing necromancers were almost to the top. I guessed the Soul Crucible would be up there. I would need to fight my way through them to get to it.
Behind me, fire roared through the necropolis. The web of necrotic energy which had been pulsing steadily was slowly flickering and dying as the arrays and structures which powered it were turned to ash.
It wasn't enough for me, though.
I closed my eyes and summoned an array around myself. Feeling the runes flare into life, I ignited them with mana and spoke the words which would link me to Sarah.
"Master!" The frightened squeak sounded loud in my ears, but I knew she wasn't close. She was already at the ziggurat's peak. "Master, I can hear you!"
"Sarah," I said fondly. "I have come for you. Are you okay?"
"Master, I can't… feel…"
"Are the others with you?"
"No. I can't see them, Master. They were here. But now they're gone."
"Can you hold on, Sarah? I will only be a few minutes."
"I…" Her voice trembled. "Is Doris safe?"
"She is."
"That's good. She was so scared. I was worried about her. I sent her as far away as I could. But we couldn't resist. We tried! Master, we tried!"
"I know you did. Can you try some more for me, Sarah? It will be over soon, I promise."
"I think…" She sighed. "Master, I can't feel my arms."
"Please try," I said, hissing through my teeth as I felt the trembling under my feet as the Soul Crucible roared loudly. The necromancers were working together. They were trying to rush their final work.
Had I done enough by stopping the hearts from coming to them?
Or had I just been wasting my time?
"Master…" Her voice shivered in my ears. "Please… I can't… All I wanted… Was to Read…"
"Sarah! Wait!"
"Master! It burns!"
"Sarah!" I screamed into the sudden roar of the Soul Crucible as light burned bright enough to light the sky.
The ground shook.
It heaved.
And I could feel the sudden glare of the Old Twit focusing on my world. On the ziggurat. On the peak.
And His thought tore through my mind like a gale.
I felt the array which had linked me to Sarah get swept aside on a wave of anguish which exploded outward to engulf the necropolis in pale purple light. The light touched everything as though the Old Twit Himself was here.
The flames, touched by the light, were warped and twisted into violet fire which burned hotter and hotter, melting through stone like it was wax.
Shadows darkened as they became vessels.
Vessels the Old Twit used to open His eyes.
And look.
The necromancers felt His gaze.
And then they felt terror.
I took my first step onto the ziggurat.
The stone melted under my feet.
I took a second, and they started screaming. Screaming as they threw condensed balls of life energy down at me. It came in a wave. A thick cloud of energy which should crash down upon me and erase me in an instant.
I held up my hand.
"Rats," I spoke. My voice resonated with the Old Twit's, and I know they could hear me. The whole world could hear me now. "You toy with things you don't understand. Come. Let me show you the true secrets of death."
I called the fire to come.
From the heavens it fell.
A rain of it.
Cometing into their ranks and blasting them apart. The violet fire raged as it leapt from one body to the next, consuming flesh with a lust which couldn't be sated. Because nothing can sate the infinite emptiness of the void.
This is why necromancy, to me, was but a plaything.
A distraction.
But one which the Old Twit had known I would learn from. The lesson had not been how to strip a soul. Or how to bend it to my will. It had not been how to forage through a pile of gore for the perfect spleen. Or how to preserve an intact brain in ectoplasmic fluid.
Oh, I had learned these things. I had committed atrocities.
But, when I gained the power to extract a soul and hold it in my hand for the first time, I had discovered something profound about existence. Something I can't put into words.
It's something you can discover for yourself.
You don't have to learn necromancy to do it.
You might find the answer in a trench while soldier die around you. You might find it in a hospital bed while someone you love drifts away from you on their last breath.
You might find it in the eyes of a pet who closes their eyes for the last time.
All of us discover it once in our lives.
The inevitability of death.
Whether it moves you or not is the difference between a gentleman and a mook.
"Stop!" Someone screamed, their arm melting off their shoulder. "We surrender! Please! We surrender!"
"It is much too late for that," I said, my voice rasping in the wind as fire slammed down from above and thundered into the ziggurat, tearing through bodies and stone alike.
Their souls cried out, their final moments full of fear and pain.
And, with a wide swing of my arm, I collected them all.
None would leave. None would find their way to the Resurrection Wheel.
Not today.
The Old Twit rumbled, heedless of the galaxies which burst beneath his writhing anger, his eyes searching. His mouths snarling and snapping.
Until he found what he was looking for.
"Lord Varis," I called, climbing each burning stair without pause. The flames parted to let me pass. But for my voice, the entire world was silent. I felt something wet slide down my cheeks. "I have come for you."