The Soul Binding Oath
The bookshelf in the secret research wing split apart, revealing a space sealed behind an intangible barrier. Leon held back from stepping through and instead circled the barrier, examining it carefully. Given that a dark mage had hidden this place, it was no surprise to find it protected like this. Try as he might, Leon could find no way to dispel the shield.
In the end, he slipped back into the Chrono Orb and once again stood before the old man’s corpse. The sight of Forn lying cold and still on the floor made Leon’s carefully steadied heart lurch once more. He shook his head, steeling himself, then searched the old man’s robes. The first thing his fingers found was a pocket of unnaturally smooth material.
Subspace pouch!
Leon poured mana into it at once and emptied its contents. Fortunately it was not a high-grade artifact; it responded to his power without resistance. Five items spilled onto the floor: a bronze token, a transparent bottle filled with green liquid, a rolled scroll, a book, and a black brooch.
The bronze token was familiar. It was the same kind the librarian carried; Leon had received one himself while running herb errands. Next came the glass bottle and its unsettling green contents.
Poison…? The color alone felt repulsive. Better not touch it carelessly.
He transferred the bottle into his own subspace pouch, then picked up the scroll beside it. The moment he unrolled it and scanned the contents, his eyes widened. It was the recipe for an E-grade elixir.
So that’s why the old man kept sending me after herbs. He was trying to brew an E-grade elixir!
He had suspected as much. Nearly every herb Forn had ordered him to gather was an ingredient absent from F-grade recipes. Leon still hadn’t collected every material needed for the lower-grade version, but possessing these would do no harm. A pleasant sense of compensation washed over him; at last the magic scrolls he had spent were paying dividends. In high spirits, he examined the remaining items.
The book was exactly what he expected: a grimoire of dark magic titled Call of the Abyss. The name was ominous, fitting for such a secretive school of sorcery. Last was the black brooch. An item stored inside a subspace pouch had to serve some purpose, yet no amount of inspection revealed its function.
Leon kept the brooch in his hand, stored the rest inside the pouch, and left the orb. Back in the old man’s study, he slowly extended the hand holding the brooch toward the barrier guarding the secret space. He made sure only the brooch touched the membrane. The instant it made contact, the brooch sank through.
Now certain, Leon pushed his entire hand inside. It passes. The black brooch was clearly a key meant to grant access. Without hesitation he stepped fully through the barrier.
Inside lay a long staircase descending into darkness. Leon walked down without pause. At the bottom, a vast cavern opened before him. The only reason he could identify it as a cavern was the soft, ambient lighting that bathed the space.
His final footstep echoed.
“Hah…”
A colossal silhouette dominated the cavern, stealing the breath from his lungs. Five times the size of a man. A long, protruding beak matched an equally elongated neck. Enormous wings enfolded a body covered in dull gray feathers.
A bird…?
It was unmistakably the form of a gigantic avian. The creature lay prostrate on the stone floor. Thin shackles encircled its ankles. Bandages wrapped its entire body, dark blood oozing between the layers. Its eyes were closed.
Only after confirming it was unconscious did Leon dare take another step. A desk stood a safe distance away.
Was he researching this bird?
On the desk lay a scroll that appeared to be an observation log. Leon picked it up and began to read.
— Further blood extraction for venom purification is no longer possible.
— Noticeable decline in overall vitality has begun.
— Consistent administration of E-grade elixir shows no measurable change.
— Currently researching alternative methods to restore the subject.
— A method for the creature to awaken its own mana? An elixir? If such a thing exists, it would prove helpful…
The final line trailed off, as though the writer had simply jotted down a passing thought. Leon pocketed the scroll and searched the rest of the desk. On the iron plate connected to it were the dried dregs of spent herbs. Beneath the plate sat a large box containing dozens of the same green potion bottles he had found in the old man’s subspace pouch. Another scroll lay on top—Week 61. Its contents were nearly identical.
Did he prepare these to send somewhere else?
Leon stored everything in his pouch but left a single green bottle on the desk. He wanted any mage who came investigating the old man’s disappearance to find it. His plan was to create the illusion that Forn had slipped out of Widia alone and returned to his own secret lair.
All that remains is deciding what to do with the bird…
It would be strange for a researcher to abandon such a specimen. As Leon stared at the creature in thought, its enormous eyes suddenly snapped open. Vertical pupils locked onto him.
“Who are you… again?”
The demonic bird’s voice echoed through the cavern—hoarse yet languid. Leon flinched, then quickly smoothed his expression.
“I’ve taken over the old man’s work as his successor.”
“Hmm… yet I sense no dark mana from you…” The bird’s words cut off for a moment, as if sneering. “It seems something has happened to that bastard Forn.”
Leon had tried to conceal his identity, but the truth had been exposed instantly. Forn was the old man’s name.
“What do you intend to do with me?” The tone was probing, almost testing him.
Leon pressed his lips together, weighing his options. Should I kill it now? If a mage discovers the body later, my tracks might be uncovered. Still… a creature that possesses reason and speaks like a person feels wrong to slaughter without cause.
Perhaps sensing the dark direction of Leon’s thoughts, the bird spoke again.
“How about we make a deal?”
“Why should I trust you?”
When Leon openly displayed his wariness, the bird stretched its long neck forward to face him directly.
“Is it not foolish to reveal your inner thoughts before even hearing the terms?”
“Is that so?”
Leon scoffed inwardly but nodded outwardly, signaling the bird to continue. No matter what it said, he held the upper hand.
“If you locate and bring me my core, I shall grant you one wish.”
“A wish? Any wish? Could you make me an archmage?”
“Mockery contributes nothing to rational conversation.”
“It just means your offer sounds ridiculous.” Leon shrugged.
His deliberate provocation seemed to have an effect. The bird’s heavy-lidded eyes fixed on him in silence for a moment.
“Have you never wished to kill someone? Anyone at all—I can kill one person for you without fail.”
The words carried an eerie weight, yet Leon’s face remained indifferent.
“I don’t want to kill anyone.”
“Impossible. Even if you feel that way now, enemies can appear at any time.”
Leon shook his head silently. Even if he did have someone he wanted dead, he would still have refused.
“…If that is not what you desire, you may take any item you wish from my lair. It would undoubtedly be of great help to your current level of magic.”
“I’m not particularly excited.”
“…Asking for my core will not be that difficult a task. Finding it will not fully restore my body in its current state. Therefore, I cannot offer anything beyond that.” The bird drew a clear line.
Only then did Leon feel genuinely willing to talk. The fact that the creature did not throw out absurd conditions even after being refused made him sense sincerity.
After a brief pause, he asked abruptly, “What would it take for your body to recover completely?”
“Long-term rest in a space rich with mana could make it possible. However, finding a location capable of supplying that much mana for an extended period is nearly a miracle. The density required is that extreme.”
Having heard enough, Leon made up his mind.
“What if I had a way to restore you fully?”
The bird snorted at once. “With your meager skill, you believe you could take me to such a place? That same meager skill would struggle to even break the shackles currently binding me. And even if you found such a location, full recovery would take decades. Could you afford to wait that long?”
“You don’t seem to be in any position to be picky. What if I really could free you and help you recover?”
Leon was already thinking about bringing the bird into the Chrono Orb. He had never taken a sentient being inside before, but it didn’t seem like it would cause any major problems. Of course, he had no intention of inviting this suspicious monster in without safeguards.
At that point the bird, seemingly exhausted, lowered its raised head and let its neck slump back to the ground.
“I know my own situation. I only speak because your claim sounds impossible. If you truly could do it, I would even form a Soul Binding Oath with you. At the very least, I could serve as your familiar until the end of your lifespan.”
“Soul Binding Oath?”
“A contract sealed with my blood through oath magic. Once formed, it cannot be broken unless one wishes to throw away their life.”
A truly reliable method. Leon nodded firmly.
“Good. Let’s do it now.”
“…Did you not hear the part about dying if the contract is broken?”
“I heard.”
The bird seemed unable to comprehend Leon’s confident attitude, yet it had no choice but to follow his lead.
“My body cannot cast magic at present, so I will teach you the formula.”
Leon precisely calculated the incantation the bird recited and manifested the spell.
"O vow formed of blood and soul,"
"twist and surge beyond the river of eternity."
⟨ Soul Binding Oath ⟩
The moment the chant left his lips, Leon’s mana drained at an alarming rate. A hexagonal magic circle bloomed in the air before him. He placed drops of his own blood and the bird’s blood upon it and recited the contract terms. In summary, Leon would provide a space where the bird could fully recover its body. In return, it would serve as his familiar until the end of his natural lifespan. Should such a place exist, the bird could not threaten Leon until its recovery was complete. Once fully healed, it would become a familiar and therefore pose no threat thereafter.
During the process, Leon learned the bird’s name.
“Kito.”
“…It has been a long time since anyone called me that.”
“The oath is properly formed, yes?”
Leon could feel the binding take hold, yet he asked anyway.
“It is… If you truly had no method, the oath would not have formed at all. It seems you do have something in mind.”
“Then I’ll release you now.”
With the oath in place, there was no reason to hesitate. Leon placed one hand on Kito’s head and gripped the Chrono Orb with the other. When he opened his eyes again, both he and Kito stood in the middle of a forest.
“This place…”
“Wait here a moment.”
Leon stepped out of the orb alone. A few seconds later he returned.
Kito was stretching her long neck in every direction, examining her surroundings.
“…How did you do that? You clearly vanished.”
“How long was I gone?”
“Only a few minutes, but…”
It seemed living creatures experienced the flow of time inside the orb the same way. I should avoid bringing people in if possible… If Leon spent a single day in the real world, anyone inside would experience two full months.
“Is the mana here dense enough for your recovery?”
Kito lifted her long neck, took a deep breath, and held it for a moment.
“…It is sufficient.”
“Then devote yourself to healing.”
Once you’re recovered, I’ll work you until you drop.
Leon’s steps did not slow after leaving the old man’s office. He headed straight for the second floor of the magic archive—the area Forn had forbidden him from entering on his very first day because it housed books of forbidden magic. He had not set foot there even once until now.
If a mage isn’t curious about forbidden magic, he isn’t a mage at all.