3rd POV:
Loud white noise was the only thing Izuku could hear currently through his ears as even his own thoughts were being drowned out by the white noise ringing in his ears. Looking down at his hands, Izuku could see them covered in blood but he couldn't remember where the blood came from but the only thing he knew was that he should be dead right now but wasn't which is why he wondered where the blood came from. The longer he spent trying to remember the more his head started to hurt and a sense of lost would wash over him. 'Something happened... what was it?' Izuku thought as he looked around to try and figure out where he was and the only thing he could see around him was some sort of cave system with a large hole in the center of the room. Pushing himself up, Izuku stumbled a bit before gaining enough strength in his lower body to stand without an issue. His body felt as if it was being held down by heavy weights but he pushed through it and started to walk around the area he was in. 'There are a few exits and one area that looked blocked.' Izuku thought to himself as he analyzed the area he was in but one thing he did notice was the sheer amount of blood across the entire room. Whatever had been bleeding was likely dead due to the amount of blood in the room.
Overall, there was nothing in the room itself with him outside of the blood but there was one last place to look which was the hole in the center of the room itself. Coming near the edge of the hole, Izuku was careful not to stumble down into it due to his weakened body but once he got next to the edge he finally remembered what had happened and why he was covered in blood. The old man had pushed him out of the way when the demonic creature went on a rampage so Miles had taken a blow that was meant for Izuku instead! Izuku remembers this all because down in the hole was the old man's body with the dead demonic creature which had been smashed under all of the rocks. Izuku made his way to another side of the hole which had enough dirt and rocks near it to get down into it which allowed him to make his way towards old man Miles. As Izuku arrived next to him with some struggle, Izuku was surprised to find that Miles was still alive but it was clear to Izuku that without modern medicine from his world or a powerful healer in this world showing up than Miles wasn't going to make it with the wounds he had! "Old man! Wake up, come on!" Izuku said as he tapped the face of Miles a bit until he woke up. "Brat..." was the first word that Miles uttered out through his bloody coughs.
~Flashback~
As both Izuku and Miles stood in front of the demonic creature, Izuku felt as if the creature just saw them as pure entrainment due to the facial expressions it was holding and that fact rubbed him the wrong way. To come to terms with the fact that he was nothing more than pure entrainment for some other entity felt like it was beyond his comprehension but then Izuku wondered if this is what animals felt like when humans pitted them against each other or they were hunted down purely for sport. However, Izuku was snapped out of his thoughts when the old man placed a hand on his shoulder once again and told him to calm down. "We need to work together and figure out a way to get to those other tunnels because it shouldn't be able to follow us into them due to the size of it." Miles said and Izuku nodded his head as he asked if he had any plans.
Izuku was met with nothing but silence as he slowly turned his head and looked at Miles. "You got a plan right?" Izuku asked but Miles shook his head to the side as he said that he didn't really have any plan since this wasn't something he encountered before. The fear that Izuku had felt before had come rushing back in full force in that tiny moment because if the old man who was a Sword Master didn't know what to do then what hope was there against such a creature? However, Miles wasn't going to give up that easily as he reminded Izuku of the fact that whenever they used Aether that the creature went on guard somewhat towards them. "If it is truly a demonic creature then our Aether may be able to counter it which means I should be able to injure it since I can apply Aether to my sword." Miles said and Izuku nodded his head as he asked what he could do to help. Miles thought it over for a bit before telling Izuku to head towards the exit when he started to fight the creature.
Izuku wanted to object but Miles said that once he got over there that he needed to start his own Aether up as well to catch the attention of the monster so that he could escape it and comes towards the exit as well. Izuku still didn't really like the plan of leaving old man miles to fight by himself since it made him feel so powerless but in this situation he was more or less a new born baby compared to miles and the creature so there was nothing else he could do about it. As such, they started the plan as Miles charged at the demonic creature with his Aether activated which made the creature put all of its attention on him and allowed Izuku to start making his way around it towards the exit.
As the fight happened between Miles and the Demonic creature, Izuku noticed that the monster attempted to dodge any attacks that had Aether enhancing it but would block anything that didn't have Aether in it. 'So Old Man Miles was right, Aether is a weakness to this creature.' Izuku thought as he kept moving towards the other side of the vast room. The closer Izuku got to the other side the more his heart would beat louder and louder due to the fight that was going on behind him since Izuku could see that Miles wasn't really winning the fight and that the creature wasn't truly putting its full strength into the fight. It was taking some damage from Miles but overall it was surface level damage that it could heal from instead of fatal injuries that would kill it.
As Izuku arrived at the other end, he turned on his aether which made the creature turn towards him and allowed Miles to dash away from the creature. Izuku though didn't expect what would happen next because once Miles had gotten half way across the room the monster gathered a beam of dark light near one of its hands causing an overwhelming sense of presence to be created. During this time, Miles turned around and met the attack head on with his Aether enhanced sword causing a blinding light to happen when the two energies collided with each other. "OLD MAN!" Izuku yelled out as he could no longer see him but felt a large shock and heard the sound of an explosion happen. Soon the light dissipated and Izuku saw a large crack had formed in the center of the room with Miles near the edge of it on one knee.
With that sight in front of him, Izuku rushed forward to grab Miles since the creature wasn't attacking and looked dazed from the bright light. It was as if all other sounds ceased to exist as Izuku thought his steps were echoing across the entire room far to loudly or that is what it sounded like to him as he ran across the room as fast as he could until he arrived next to the old man. "Come on... let's get out of here!" Izuku said as he lifted the old man to lean on one of his shoulders and started to walk away but after only a few steps a ear piercing scream happened as the creature was no longer dazed. "Oh shit..." Izuku said in a low tone as he looked behind him at the creature that clearly had an expression of pure anger on its face even though it wasn't a face of a human but one of a monster. The monster pushed forward from the ground and came charging towards both of them which shook the cave due to the sheer size of the monster.
Raising one of its limbs, the monster swung downwards towards them but Izuku was able to push both himself and Miles out of the way in time of the demonic creature's hand coming down onto the ground which caused a large pressure of air to push away from the spot. The one thought that came through Izuku's mind when the creature pulled its hand back was how it would have turned them into pure mush if it had landed that blow because on the ground was now a complete handprint from the monster. However, this wasn't the time to let his thoughts wander as the monster was gearing up for another attack so Izuku worked quickly to move them out of the way but as they were moving forward Izuku ended up tripping over some of the rubble that had fallen from the ceiling.
Thus, Izuku and Miles were in the direct path of the incoming attack and Izuku had no way of moving them out of the way in time. As the hand grew closer, it was as if time came to a crawl as Izuku felt a spike of Aether to his side that was so large it shocked him. Slowly turning his head, he witnessed Miles stand up from the ground and raising his sword into the air as he sliced upwards causing a large gush of wind pressure to blow away from his blade and landing against the ceiling. The monster had dodged the wind pressure generated from Miles sword since it had lingering Aether in it but was unable to dodge the falling ceiling that came tumbling down upon it. The next thing Izuku knew was the fact that he was flying through the air away from where he had just been. Coming out of his shock, Izuku was left with the sight that would haunt him for a long time as he was too far away to do anything but watch and that is what he did. With his eyes wide open, Izuku saw the ceiling come down on not only the monster but Miles as well as blood spattered across the room from the monster. In these few moments Izuku felt as he could no longer breath as darkness soon took over his vision and that became the last sight he saw before everything went completely black.
~Flashback end~
This was how it happened as Izuku's memories finally came back to him and the horror he now felt was indescribable as the only thing he could do was to hold the dying man in his arms. "Old man... why!? You weren't meant to die here! This was meant to be a simple mission.... A... a mission where... GOD DAMMNIT OLD MAN!" Izuku said as he yelled out in anger. Miles just leaned his head a bit to the side in Izuku's lap and looked at him with a small smile on his face. "Kid... you got to learn not to cry so much.... Makes you looks too much like a stinky brat." Miles said with some blood running down his mouth as he spoke each word causing the fear in Izuku's heart to only grip more tightly. Izuku just sat there in silence since he didn't know what to do but after a few seconds which felt like hours to Izuku, Miles reached into his clothing behind his chest plate and pulled out a sealed envelope. "Izuku...." Miles said but that small action caused him to cough up a large amount of blood since he shouldn't have moved his body as it only hasnted his coming death but Miles knew he needed to say what he needed to say before it was to late.
"Kid, I know.... I know we didn't get to finish training but you know everything you need to finish..... I want you to take this letter and envelope and head out west and grow stronger.... If you ever need.... Help..... An old friend lives out that way and he's.... a noble in one of kingdoms." Miles said as he explained that the man could help Izuku in his travels as a repayment of debts if Izuku ever needed it. Izuku gripped the envelope and nodded his head but he was barely containing himself as he listened to the man he had seen as a father figure in this new world. After another 10 minutes or so, Miles finally took his last breath as he passed away and in that silent moment, Izuku felt as if everything he had done in regards to his training and desire to go home weren't worth all the time he spent because in the end he failed to protect someone he had cared about.
After a few more minutes of silence, Izuku pushed himself upwards and walked over to the demonic monster as he made sure to get a proof of subjugation as the guild needed to know what had happened here and he needed proof of its existence. It wasn't about the money or the monster at this point... no, it was about the deep rooted hatred and anger that Izuku was feeling at the moment as he wanted the three adventures who destroyed the tunnel to pay for what they had caused. Izuku knew that the demonic monster was the cause of Miles death but it wasn't the reason that he was now dead... no, that belonged to the three adventures solely and Izuku was sure of one thing and that he was going to make them pay no matter what! As such, he climbed his way up the dirt and rocks with one step at a time as his hands dug into the rubble causing his fingernails to bleed due to how hard he was digging them into it but he didn't care about his own wellbeing right now.
Making his way towards the two exits, Izuku debated for a few moments on which way to go before he tossed a coin in the air. "Heads I go left.... Tails then I go right." Izuku muttered and as the coin landed in his hand he saw it landed on the head side of the coin. "Left I go." Izuku said to no one but himself as he marched into the tunnel with his blade ready. As he kept walking, Izuku could hear some sounds the further he got into the tunnel and the further he went the louder they became until he could hear them more clearly enough to tell that they belonged to humans. Picking up his pace, Izuku soon arrived at the end of the tunnel where he found both of the other squads fighting a hoard of goblins and a few hobgoblins. Looking around, Izuku found the guild master and made his way towards the man as he was fighting several hobgoblins at once. With quick steps, Izuku pushed himself into the air and right into the back of one of the hobgoblins causing it to go down towards the ground and within seconds, Izuku pieced the back of its neck with his sword.
"Oi, where's Miles at?" asked the guild master as he saw Izuku take out a hobgoblin but Izuku only answer concerned the man, "Gone." Izuku said as he charged forward at another monster and kept going after another and then another as he wanted to get all of this anger out of him but it kept building up more and more due to the fact that the three individuals responsible for the old man and him being trapped with that thing are nowhere to be found currently. After a period of fighting, the monsters were subjugated and everyone noticed Izuku presence more cealrly now as they were confused on why a member of the third squad was here without any other squad members around. Both of the squad leaders that remained walked up to Izuku and asked him point blank on where Miles and the rest of the squad was. Turning to the guild master, Izukus eyes told the man many thing and in that second of gazing into Izuku's eyes he believed he had the answer. "Your squad was wiped out wasn't it?" asked the guild master and that statement caused the entire room of adventures to come to a complete standstill of dead silence.
"Not everyone but I am what remains inside of the lair... we were retreating when those three bastards caved the tunnel in before we got out... they trapped us with that thing...." Izuku said and everyone was confused on what Izuku was talking about expect the squad leaders who knew about the three schemers who were talking about killing someone. "I see they acted.... Miles or you was the target it seems." Said the Guild Master and Izuku nodded his head but said that they would have been fine if it was some normal monster but it wasn't. "Explain? Did you run into the Goblin King? Even then Miles should have been enough to handle it even in his old age." Inquired the guild master as he knew the skills of Miles quite well since they had known each other for a long period of time. "No... it wasn't a monster... not what the old man believed. It was something of past eras... He said it was a demon from long ago history." Izuku said as he pulled out the proof of subjugation that he took from the corpse and you could still feel the energy coming off the corpse even though it was away from the main body. Izuku explained what had happened in the other room and that the demonic creature was dead but that it had wiped out so many of the squad that Miles ordered a retreat but that both of them in the end were trapped with it which led to Miles death because of how strong the monster was.
After more minutes of silence, the guild master ordered everyone to gather as they would finish cleaning the lair and ensure that there was no other demonic creatures inside of it. He had believed that the Goblin King had been taken over by a demon somehow as a vessel but he wanted to make sure there wasn't anything left in the lair since there was that one path left in the other room where Izuku's squad was wiped out. Before they set off though, the guild master gave out an order that the three adventurers were to be detained if they came across them inside of the cave which made Izuku grip his hands tightly as he wanted the three to pay with their lives for being the reason the old man was dead. As everyone moved away, the guild master stopped Izuku and looked at him in the eyes, "I know what you want to do and trust me... it will be done one way or another." Said the man before he pulled Izuku towards the path as they set off to clear the rest of the lair.