Chapter 1: The Contract of the Tenth Summoner
It all began five years ago.
Scientists discovered four atmospheric layers around the Earth. These barriers acted as shields, preventing sub-atomic particles and cosmic cosmic substances from reaching the surface. However, the fourth layer unexpectedly vanished. As a result, a mystical energy known as Mana began to permeate our world, and humanity discovered the art of Magic.
But the joy was short-lived. Soon, two gates to other dimensions tore through the sky:
The Spirit Realm.
The Realm of the Dead.
That same year, I awakened my magic. To my family's dismay, my mana levels were abysmally low. Both my parents were elite mages, but I could only gather a faint amount of mana around my weapon for a single strike. I was a failure in their eyes.
Then, during my mundane daily life, I obtained an extraordinary power: The Seal of the Tenth Summoner. It is said that only ten chosen individuals in the world possess this crest. It awakens only after one's ordinary magic has manifested.
Without hesitation, I activated the summoning ritual.
As the spell gathered strength, a Spirit Soldier spotted me from a distance. I thought I could finish the summon and escape, but I was wrong. The spirit was faster. It lunged at me, raising its spectral blade. My heart hammered against my ribs—I hadn't fought in ages. Fear gripped me.
"I don't care how much mana you take! Just be fast!" I roared in my mind, pouring every ounce of my energy into the seal.
Just as the Spirit Soldier's blade was about to descend, a heavily armored figure materialized from the light. With a single, devastating blow to the spirit's chest, the soldier was obliterated into mana shards.
I stood there, breathless, trying to keep my composure.
The armored figure turned toward me and knelt. "Did you summon me?"
"Yes," I managed to say.
"Then my name is Rina. From this day forth, I shall be your servant for three years. However..." she paused, her voice sweet yet firm. "If you agree to grant me half of your life force, I shall stay by your side forever."
Judging by her height and voice, she looked about sixteen—my age.
"Can you... remove your helmet?" I asked.
"As you wish."
When she took off her helmet, I froze. I had seen beautiful girls before, but she was different. Her long, raven-black hair fell past her shoulders. Her skin was flawless, without a single scar, and her eyes were a deep, mesmerizing sky-blue.
We talked for a long time. She explained her goal: to restore order to the Spirit Realm and return it to its former three-tier hierarchy. I told her honestly that I was aimless—I had nothing to lose and nowhere to go.
Then, an idea struck me. "Hey, Rina. If I help you take control of the Spirit Realm, will you stay with me forever?"
I wasn't asking for romance; I was asking for survival. She understood this and agreed.
"But there is a problem," she added. "Our current contract is only for three years. My calculations show this war will last at least five. I won't be here when it ends."
"Is there a way to extend it?"
"There is, but it's a massive gamble. You must give me half of your Life Force. If you do, I will be bound to you eternally. I won't be able to leave you even if I wanted to."
"What exactly is Life Force?" I asked.
"It determines your longevity and potential. If it's high, you can become a legendary hero or mage. If it's low, you will not only be weak but your life will be short."
"Can you see how much I have?"
"No. I can only sense it, absorb it, or transfer it."
I didn't hesitate. "Do it. Take it."
She looked startled. "Aren't you afraid? If your life force is low, you will die instantly."
"I have nothing left to fear," I said coldly. "Everyone I cared about is dead. If you had come six months ago, maybe I would have hesitated. But not now."
"I understand."
She stepped closer and placed her hand on my forehead. I closed my eyes, feeling a strange sensation flowing out of my core. After a moment, she pulled away.
"It is done."
I opened my eyes. I was still breathing. A surge of relief washed over me—it seemed my life force was more than sufficient.
"Alright then, Rina. Prepare yourself. We're going to gather enough power to conquer the Spirit Realm together."
Five Years Later...
Are you ready?"
"Yes."
"In precisely thirty minutes, the Fourth Layer will reappear. The Spirit Realm and the Realm of the Dead will be severed from Earth. We have to move now."
"Then let's head to the Gate."
Five years ago, I stood before this very portal, and it had rejected me. I was too weak, too insignificant. Now, half a decade of blood and mana later, I stood before it again. Will you accept me this time?
The Gate didn't just open; it trembled. We stepped through, entering the Spirit Realm—a place of no return for any ordinary mortal.
Twenty Years Later...
I sat upon the obsidian throne in the central hall of a sprawling fortress. Rina stood faithfully by my side.
"It's fascinating, Rina," I remarked, looking at my hands. "Twenty years have passed, yet I haven't aged a single day. Eternal youth... the Spirit Realm certainly has its perks."
Rina looked at me, her expression as calm as a frozen lake. "You have something else on your mind, don't you?"
I chuckled. "You always were too quick for me. Yes. Finally, we can return to the mortal world. But not to the Earth we knew. It's more like... an 'Isekai.' A different world entirely."
"How is that possible?" she asked.
"I had 'variants' of myself in other dimensions. As we clawed our way to power, they fell one by one. Now, only one remains. I will transfer my soul into his dying body, and once I'm settled, I'll use our contract to summon you."
She didn't look thrilled, but I could sense her boredom with this desolate realm. She was ready for a change.
"Soul Transference... begin!"
I tore open a massive rift in space-time. This wasn't ordinary magic; it was the ultimate art of moving a soul between vessels.
The New World
I gasped as my eyes snapped open. The scent of fresh grass and the sound of rustling leaves hit me instantly. I took a deep, jagged breath and screamed at the top of my lungs:
"I'M BAAAAAAAACK!"
Apparently, someone didn't appreciate the noise. A dagger hissed through the air, aimed straight for my throat.
Damn it! I remembered striking this body's previous owner in the neck—wait, no, I had aimed for the brain. No wonder the poor guy was screaming before I took over.
"Kill him again! Make sure he stays dead this time!" a voice roared.
I realized with a jolt of panic that I had stepped into this body too soon. The assassins who killed the original 'me' hadn't even left yet! I looked at my hands; they were thin, lacking the calluses of a warrior.
This body... it's weak. It's me at sixteen, before I ever found Rina.
"Can't we just talk this out?" I asked with a smirk, dodging the next dagger with a fluid motion. My Spirit Lord instincts were still there, even if the muscles hadn't caught up yet.
"Die!"
The assassin lunged with a combat knife. Negotiations were clearly off the table.
Fine. I caught his wrist, feeling the fragility of my current arm. I didn't need brute strength, though. I gathered every drop of Mana I could find into my palm and slammed it into his solar plexus.
The pressure wave was internal. He didn't just fly back; he coughed up a spray of crimson and collapsed, his internals shredded by the concentrated mana burst.