The Weight of an Oath

Honestly, I wanted to enjoy this a little longer. I could have used the curse hindering my healing as an excuse to ask Yujin to burn me, or maybe tell him my limbs felt like they were rotting from the tips and ask him to chop them off. If the situation had allowed it, I really would have gone through with it. But unfortunately, now was not the time to indulge in ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠my hobbies. Nothing had been resolved yet. The Rift in Space was still spewing out monsters, and we had only managed to defeat a single Black Knight. No, actually, we hadn't even completely defeated him, so that phrasing was incorrect.

"Ugh... *cough*, *wheeze*!" I tried to swallow the blood rushing up my esophagus, but ended up coughing it up anyway. It felt wonderfully hazy and fluffy, which was great, but I'd lost so much blood that my body was turning ice-cold. Since my heart wasn't beating, my blood circulation was practically nonexistent. If I left it like this, I'd pass out. Right, I can't afford to be a burden. Shall I start regenerating now?

The Black Knight's deathly energy was clinging stubbornly to me, hindering my healing, but my Super Regeneration was more than enough to overcome it. Fortunately, the Black Knight had only viewed me as an annoying pest, not an opponent he needed to kill with all his might. Well, that's exactly why my surprise attack succeeded. Weakness can be a useful tool sometimes, you know? If I had been stronger, the Black Knight would have been on guard, and if he had condensed his deathly energy into his longsword, even Super Regeneration wouldn't have healed it so easily. In other words, if Lucia gets hit by that, even she would be in big trouble.

"Watch... out..." Naturally, I was the first to notice the anomaly. Yujin and Frey were so focused on me that they didn't have the leeway to look behind them. I wonder if they forgot this is a battlefield. If your back is that defenseless, you're practically begging for a surprise attack, you know?

"...!" Belatedly realizing the danger, Yujin's expression froze. It's not like he has eyes in the back of his head, so did he sense it purely by presence? Finally, Frey also sensed something amiss and tore her gaze away from me. They slowly turned their heads. A black haze was undulating in the air.

The Black Knight, who had been sprawled on the ground like an empty tin can, was changing. He still lacked his right arm, and the space where his head should be remained hollowly vacant. Nothing about his form had changed, but his position had. Defying gravity, the pitch-black armor floated into the air. An ominous black mist swirled violently around him.

"What the hell? I thought he was dead!" Frey muttered, slightly flustered. I nodded in agreement, though they probably didn't see me since their eyes were glued to the Black Knight. The Black Knight was dead. His core must have been shattered. To put it simply, what we were seeing was a rampage. An immense amount of deathly energy, which even the Black Knight himself couldn't fully control, had lost its anchor inside the pitch-black armor and was now running wild.

The ground withered and cracked. The vegetation, which had somehow survived the fierce battle, rotted away into mush. The wind carried a nauseating stench, like decaying flesh. With the dead Black Knight at the center, the world itself was dying. This was the "cleanup" I had mentioned earlier. If left alone, it would spread indefinitely. The park would become a wasteland where humans could never set foot again. It might even spread beyond the park's borders.

This was a problem that could be solved if a Supernatural Ability User with exceptional destructive power blasted the Black Knight's corpse along with the deathly energy. Conveniently, we had Yujin, who controlled fire, and Frey, whose abilities were specialized in raw firepower. The phrase "perfect fit" was made for moments like this. I looked at them with expectant eyes, but then I flinched involuntarily. Uh, well... Yujin's expression was incredibly cold. Actually, not just Yujin—Frey looked similar. Anyway, they looked absolutely furious. But it was the kind of expression where they were tightly suppressing their rage.

Um, excuse me... are you mad? Well, I guess it's only natural, right? Seeing their friend get impaled right in front of them. Besides, Yujin and I are best friends. Well, not officially yet, but we promised to be. It was actually a pretty great look on him. It's always the quiet, gentle ones who are the scariest when they get angry. *He-he*, my chest is tingling with goosebumps. I almost want to ask him to slap my cheeks. Or maybe step on my head. Honestly, Yujin is so nice that even if I asked him to do something extreme to me, he'd probably do it half-heartedly... but *he-het*, looking ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠at that face, I feel like he'd do it properly when the time comes. No joke, my heart actually skipped a beat. It felt like it plunged straight down. I almost called him "Master" without thinking. I didn't know Yujin could make a face like that...

It's happening again. Just like last time. And now, this time too. The exact same situation repeats itself. I boasted so proudly that I would save everyone. Lucia, the citizens, everyone. I said I would save them all. So why is it turning out like this again?

...It's hot. Yujin looked down at his trembling palm. Unable to withstand the heat, the dried blood had turned a dark, muddy color. It was his own blood, and at the same time, Lucia's. They were already mixed together, making any attempt to distinguish them meaningless. Yujin slowly curled his blood-scented hand. His fist shook violently. His veins bulged, looking as if they might burst at any second. He clenched so hard that his fingernails dug deep into his palm, yet he didn't loosen his grip. The fact that his nails—which he always kept neatly trimmed so they wouldn't interfere with his swordsmanship—were tearing his own flesh was proof that Yujin was practically self-harming.

His heart pounded as if it would explode. His head throbbed. His entire body ached so intensely that he felt he would shatter into pieces if he didn't release his emotions right this instant. But merely wounding his palm ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠did nothing to ease the turmoil inside him. If anything, it only fanned the flames. Such trivial pain only fueled Yujin's fury. They had won, but they had lost. That battle was Yujin's defeat. The onslaught had been fierce, and every single blow had been devastating. It was hard enough just to endure, let alone counterattack. He had held out as long as he could, but it hadn't lasted. The Sun Sword had been deflected, leaving Yujin completely defenseless. The Black Knight's longsword had been aimed precisely at Yujin's heart. Yet, the one whose heart was pierced was not Yujin, but Lucia. It was a miserable, utter defeat. If Lucia hadn't intervened, Yujin would be a cold corpse by now. How many times had this been? First on the bus. Then during the high-tier monster's surprise attack. And now, from the Black Knight's strike.

...My chest is burning. His emotions surged, throwing him into an uncontrollable state of agitation. Ah, he had experienced this before. That day. That time. That very moment. The day he had broken his oath out of sheer terror of Astaroth. That time he had trembled pathetically, unable to do a single thing. That moment he had been consumed by self-loathing afterward. He was all talk. He babbled on with grand words, but he lacked the power to back them up. He had shouted that he would protect everyone, yet there were countless people he had failed to save. He had said he would protect Lucia, but in the end, who was the one being protected? He only spouted plausible lies, never once keeping his word.

The sword had pierced her chest. He had grabbed her shoulders to stop her from thrashing. He remembered the trembling transmitted through his hands, and how she had forced a smile to hide her pain-contorted face.

"W-Watch out... Yujin, your wounds..."

Those were not words someone with a sword through their heart should be saying. Even in that state, she had put others before herself. Amidst pain so excruciating that she couldn't even scream, she had forced a smile just to keep him from worrying.

What do I mean, "I'll protect you"... When it actually mattered, he had done absolutely nothing. At best, all he could do was hold her shoulders so her wounds wouldn't tear further, and tell a white lie that wouldn't fool a soul. What on earth had gone wrong? Where did it start to go astray? From the moment the Black Knight appeared? Or when the Rift in Space opened? When that child in the white cloud mask dragged Lucia over, chopped into pieces? When Astaroth came walking toward them, waving her hand? No. That wasn't it. It was all wrong. It was fundamentally, miserably wrong from the very beginning.

It's because I'm weak. Yes. That was the problem. If only he were stronger. If only he were strong enough to defeat any monster that appeared, or any entity claiming to be a Main that attacked them. If he had been that strong, Lucia wouldn't have needed to sacrifice herself. There would have been no hole pierced through her chest, no blood foaming from her mouth, and no reason for her to look up at him with tear-filled eyes.

It's infuriating. His chest burned. He couldn't control the intense impulse surging within ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠him. It roared, threatening to swallow his sanity whole. It's so frustrating. It was always like this. Yujin was always weak. When his beloved family was murdered. When the person he cared about collapsed, bleeding out. His weakness was infuriating. He hated himself so much.

"..." Yujin stepped forward. The headless remains of the Black Knight were draining the surrounding vitality. It greedily devoured the life around it, as if attempting a double suicide with the world itself. Everything faded. Everything was dyed in shades of gray. The weeds, the shattered cherry blossom trees, the blue sky, the cracked Rift in Space—even the pitch-black armor. But the color of the flickering flames could not be stolen.

He knew that an oath only had meaning when kept. He had sworn never to run away again. But even if he didn't run, if he lacked the strength, it was no different from fleeing. What value was there in an oath he couldn't keep? Therefore... I must become stronger. So that I can protect everyone. Because "everyone" must include you.