The Gehenna Prison Fortress was, as the name suggested, both a prison and a fortress. However, as evidenced by the Dawn Army ignoring the Gehenna Fortress and advancing straight to the capital Ushak, it was hardly a strategic stronghold, its role as a prison being far more significant. Of course, if Dead December had intended to, he could have moved the forces stationed within the fortress to strike the Dawn Army from behind. But Isaac was certain that such a thing would not have happened. Because at that time, the Outer Boundary was already in turmoil. "The Gehenna Fortress is connected to the Outer Boundary." Isaac explained briefly to Isolde as he stepped into the Gehenna Fortress. Isolde asked, bewildered, "What? Isn’t the distance from here to the Outer Boundary quite far?" "The Outer Boundary is, quite literally, the edge of the world, the boundary of civilization. If there is sufficient space underground, the Outer Boundary can writhe. Especially in places untouched by sunlight." Rare, but such places existed even in the Empire. Land rumored to be cursed, or where people frequently died for reasons unknown. Such places often had a high probability of having a Subterranean Outer Boundary deep underground. Isaac speculated that the White Owl’s graveyard beneath the Issacrea estate was also related to the Subterranean Outer Boundary. But Gehenna was definitely, perhaps, connected to the largest Subterranean Outer Boundary on the continent. "I don’t know when it was connected. According to the traces discovered, it was initially developed as a coal mine, then a temple serving an ancient god, and then, with the birth of the Immortal Order, it was reborn as a prison fortress. Perhaps its history is quite old." The Immortal Emperor was just as averse to the Outer Boundary. When Holy Land Lua was attacked by monsters from the Outer Boundary due to Isaac’s machinations, it was only natural that he ordered Dead December to guard the Gehenna Fortress instead of sending reinforcements. In his view, the situation of monsters from the Outer Boundary emerging from the Gehenna Fortress in the heart of the Empire would have been terrible enough. "Dead December chose the path of burying himself alive here and becoming an Archangel to protect it. To seal away those who threatened the Immortal Order, and to prevent even more terrible things from rising to the surface." Let’s correct that. The Gehenna Fortress was strategically important. The Gehenna Fortress was adequately fulfilling its role as a guardian. To protect civilization from the enemy of all mankind, not just the enemies of the Immortal Order. Linde, who had been silently leading the way and listening to the story, turned back in disbelief. [...I’m hearing this for the first time, but Your Excellency the Regent seems to know all sorts of stories.] "I just overheard it," Isaac said shamelessly. Before they knew it, they were stepping into the entrance of the Gehenna Fortress. The granite fortress, precariously built on a steep cliff, was so sturdy that even if an angel invaded and unleashed his wrath, it would be difficult to leave a scratch. At the end of the bridge, there was nothing that looked like a door, but as they approached, a thin gap opened and a heavy sound echoed. Just like the dome of Holy Land Lua, the stone door inscribed with all sorts of blessings and prayers from the Immortal Order moved and opened entirely. Even if someone trying to escape from the prison managed to overcome the obstacles and climb up, what they would ultimately face would be this massive lid and a bottomless cliff. Of course, before that, they would have to face the giant gatekeeper behind the door. Squeak, squeak, squeak squeak. Something crawled beyond the pitch-black darkness, making an eerie sound. Although it was hard to see as if obscured by artificial darkness, they could clearly feel the eerie murderous intent and gleaming gaze. Even Isolde seemed to sense the presence, as she looked around nervously. After the Immortal Emperor disappeared, the eternal winter disappeared from the Urdantu Empire, but the inside of the Gehenna Fortress was still so cold that it was chilling. It was impossible to guess how many undead were waiting in the underground. Linde stepped forward first and spoke into the air. [Archangel Dead December, I am Amarinde, a humble follower leading the Avalanche Knight Order. As you commanded, I have succeeded in meeting Isolde Brant and summoning the Holy Grail Knight back into this world.] She sent the message with a frequency that Isaac and Isolde could also hear. [As you foresaw, His Majesty the Emperor resides within Isaac’s soul. However...] [You have done well, Amarinde.] The voice of Dead December cut off Linde as she tried to defend Isaac’s position and convey the Immortal Emperor’s words. Soon, a faint form began to appear in the air. The Archangel who had buried himself beneath the massive prison and embraced eternal winter revealed himself. Of course, since his main body was still at the bottom of the prison, he only revealed a part of his soul, as Isaac had encountered in the Nightmare Strait. It was difficult to distinguish which part was the body and which part was the head of the monk’s figure entangled with a giant old tree. [I have heard all about your journey, hardships, and adversities through Al Theodore. You have accomplished great things in a situation where the Immortal Emperor’s grace could not watch over you. I commend your achievements once again.] Linde knelt down, seemingly moved by the Archangel’s praise. It was rare for the Archangel to give such high praise. But on the other hand, she felt uneasy. Dead December was only praising her for bringing Isaac, and was not trying to speak directly with Isaac. Even though Dead December knew better that the Immortal Emperor was inside Isaac’s body. [Your scattered knights are resting underground. Al Theodore should also go down and meet them. I will... speak with the Holy Grail Knight.] [Thank you for your consideration, Dead December, but...] The moment she tried to convey Isaac’s position once more, a powerful aura of soul enveloped the surroundings. Linde prostrated herself with both hands on the floor, and Isolde also staggered as if feeling dizzy. At that moment, Isaac wrapped his arm around her shoulder. As a warm energy enveloped her, Isolde felt strength returning to her legs that were about to give way. "Let’s talk without being impatient, Dead December. It’s not a big deal for you whether Commander Linde is here or not." Dead December stared intently at Isaac. Even if the Archangel revealed his aura only a little stronger, ordinary humans would faint or their hearts would stop. But Isaac did not seem to be affected at all. It was an absurd growth compared to when they had met in the Nightmare Strait. "I came in knowing it was a trap anyway. I have no intention of running away, so you can be honest." Isolde and Linde were not greatly surprised by the word "trap". They were already well aware of the possibility that things would not go smoothly. Leaving Isaac as he was now was connected to the legitimacy of the Immortal Order. Acknowledging a tentacle monster who neither died nor had its flesh carved off as the Immortal Emperor’s proxy? It was hard to believe even if the Immortal Emperor had left a direct will. The issue of legitimacy was always a problem that shook the foundations of faith and dynasty. Among them, Dead December, the first Archangel of the Immortal Order, was a fundamentalist of fundamentalists. Dead December said with a growl. [I know what happened in Holy Land Lua. I could not use my power directly, but I saw what happened from afar. How you assassinated His Majesty the Emperor, how you devoured his body, and how you forced your will upon him.] "Then there’s nothing to explain." [How dare you, after doing such a thing, claim to represent the will of the Immortal Emperor!] "Hah, you’re talking arrogantly. What I did is not important." Isaac retorted, dumbfounded. "What’s important is whether the Immortal Emperor tolerated my existence and accepted his will. Can you dare to say that you made a better judgment than the Immortal Emperor? You, a warden who’s stuck in a small room counting prisoners?" Linde had expected to face some difficulties in persuasion, but she was astonished by Isaac’s tone. Isaac seemed to have no interest in persuasion. He was talking as he pleased, as if he would smash Dead December and the Gehenna Fortress and do what he had to do. She believed that it was right to follow the will of the Immortal Emperor rather than Dead December for now, so she prepared for the worst. The sound of something unidentified crawling on the ceiling, lightly tapping the stone wall, did not stop. After a moment of silence, Dead December spoke again. [That can’t be. The Immortal Emperor always makes the right judgments.] [Then I’ll have to cut open your belly and hear His Majesty the Emperor’s command directly. Don’t worry. People don’t die easily these days. Even if you die, I’ll revive you as a beautiful skeleton...] Isaac also felt the sound echoing from the ceiling intensifying. Since he knew it was a trap thanks to the White Owl, Isaac had come up with his own countermeasures, thinking that persuasion would not work. [Tear open his belly, Kerrasentine!] From the pitch-black darkness, a giant skeletal centipede revealed itself. It was not a real skeleton, but a madly formed shape made by stringing together hundreds and thousands of monsters and undead. No one can leave the Gehenna Prison except the guards. The prisoners cannot escape this prison even in death, and their bones are woven together to serve as the final gatekeeper, preventing other prisoners from leaving. ’Gehenna Fortress’s Watchdog, Undead Centipede Kerrasentine’ Isaac knows about it well. The Gehenna Prison Fortress is an impregnable fortress both inside and out. Those who try to break through the fortress must first defeat the Undead Centipede, and those who try to escape will face the Undead Centipede for the last time. The final ordeal of the Gehenna Fortress. That is the Undead Centipede named ’Kerrasentine’. Get full chapters from novel⟡fire.net Its power, which has been cultivated by eating countless bones, souls, and weapons for hundreds of years, is comparable to a powerful Gicheonsa. Hundreds of hands and feet, teeth, and sharp bones flew in disorder to attack Isaac. At the very front of the centipede was a giant skull and a scythe as big as a house. The moment Linde pulled Isolde back to protect her, Isaac moved. The Luadin Key was drawn out, emitting a brilliant radiance. The Luadin Key, which had absorbed the heat of the Lighthouse poured out by Ramiel, was shining so brightly that it was almost comparable to the light emitted by the Watcher’s Lighthouse. After the battle with Ramiel, Isaac had been wondering about the state of the Luadin Key. It did not have such powerful defensive capabilities before. But the Luadin Key was emitting a distinctly clearer light, and Isaac now felt the energy of the ’Sword of O’Wol’ inside the sword. The Luadin Key had been reforged and imbued with power by the Sword of O’Wol in the past. And in Holy Land Lua, her power permeated Isaac, further strengthening the power of the Luadin Key. The Holy Sword used by an angel was bound to be qualitatively different from the Holy Sword used by an ordinary Paladin. And now that the Sword of O’Wol was closer, the Luadin Key burned even brighter as if responding to that power. Isaac showed its performance directly to Dead December. The Luadin Key reproduced the thermal ray that the Lighthouse had emitted in the Gehenna Fortress as it is. Kerrasentine writhed with its whole body burning from the terrible destructive power. [How can such a barbaric...!] Dead December was also flustered by the power and hastily pulled up the cold air inside Gehenna. The cold air, like a freezer, quickly covered the surroundings, and the flames went out, causing massive steam to rise. What Isaac was aiming for was that steam. As the heat that the Luadin Key had contained was exhausted, Isaac hurriedly shouted to Linde and Isolde. Isaac had no intention of having a head-on confrontation with Kerrasentine. Although he had awakened to the power of murder, it was still impossible to kill the Undead. Isaac thought that he was not killing ’anything’, but perhaps closer to returning it to the state ’before the Millennium Kingdom’. He had even devoured the Immortal Emperor, so he thought that a watchdog would not be a problem, but the Gehenna Fortress did not only have that trial, and he might have to ultimately face Dead December. There was no need to fight an enemy that could be avoided. The three hurriedly started running. Linde, who knew the structure of the Gehenna Fortress, took the lead and opened a door that only the Undead could open, just like the one in Holy Land Lua. Linde shouted to Isaac, who was running down the stairs with her, [Is this the entirety of the strategy, Your Excellency the Regent? Distracting them and running away into a deeper maze?] "I can’t fight the whole fortress. If we just go down to the bottom, we’ll win." To defeat Dead December, they had to go down to the bottom of this fortress. Coincidentally, Gebel and the Sword of O’Wol were also near the bottom.