Lower moon

'Shit!' 

I ducked under her staff and rolled forwards into the opposite wall, though not before its pointed end managed to draw blood from my forehead. 

"Where do you think you're going?" She turned around to look at me. I only looked back for a second before I hauled ass and jumped out the hatch and shut it behind me.

Once back on the main floor, I drew my blade out of its scabbard, gripping the hilt with both hands while the tip of the sword was pointed towards the hatch.

I couldn't hear any sound coming from below, giving me no confirmation the demon is still in there. I kept my eyes wide open, waiting for any indication of movement so I knew where and what to point my blade at.

A cold sweat enveloped my body as blood from my wound started flowing down into my left eye, limiting my field of view.

"You didn't think you could trap me there did you?" The woman laughed, now standing just a few feet in front of me with a small grin on her face.

'How? Is there another exit? No, she just appeared there. Teleport-' my thoughts were cut short as the woman extended her bo staff, thrusting it towards me like a spear.

'Dead calm, Overload' 

All my body movements were halted, replaced by a soothing sense of tranquility, the raging waters of my consciousness now completely still and uniform. Even in the face of danger, breathing styles still worked wonders.

I began blocking every single thrust the demon threw at me. Yet her expression never changed, she simply stopped attacking and hit the ground beneath with her staff.

With that, she disappeared. Reappearing to my side only a fraction of a second later, her bo staff angled horizontally and aimed towards my head.

I intercepted it with dead calm, yet the sheer force of the strike sent me stumbling, my left arm enveloped in a dull pain.

She took advantage of my balance and thrust the pointed end of the staff towards my skull. Yet just as it was about to pierce it and kill me, her weapon suddenly disappeared from her hand. She opened her eyes wide while dodging another one of my attacks and jumping backwards.

"Well, that's unfortunate. You're a lucky kid. No matter though, I can see your fortune, it reeks of death." 

I used this short pause in the fight to analyze my opponent. She still looked very much like a human, short stature, almost as short as me, short black hair reaching down to her chin and a set of deep blue eyes. Yet her horrifically pale skin and two goat horns curving from behind her ears and forwards gave away that she was anything but human. 

When I took a closer look at the woman's left eye, I noticed something odd. Something had been etched into it.

"Lower moon five?" I said out loud.

"That's right, aren't I lucky? Fortune was with me on that fateful night, for my superior died at the hand of a demon slayer, but I survived  and I was instantly promoted." She said, acting out her words as though she was performing in front of an audience.

After saying those words, her expression went cold, her smile disappeared along with the mark in her eye, as both eyes started spinning like slot machines, eventually landing on something I couldn't make out. 

"Witness my truly blessed blood demon art!" She yelled out.

I gripped my sword tighter.

"Hahaha, fortune really is with me tonight!" Another staff appeared in her hands, this one slightly smaller and red in color.

From the staff, she drew a short, straight sword.

During all this, I kept my eyes on my opponent. A single mistake meant death, and against an opponent seemingly capable of using magic, charging in blindly was akin to a death sentence.

She gripped her thin sword with one hand, and charged at me. As soon as she got within range, I swung my sword diagonally toward her head.

'Water surface slash.' 

Her blade raised to meet mine, yet instead of clashing, her sword went right through mine, cutting off the fingers that gripped it while she sidestepped away from my swing.

I tried backing away, yet she was already on my left side after dodging my blade, taking advantage of my limited field of view. 

Still in my blind stop, she swung horizontally, aiming for my left arm. One again I tried meeting her sword with mine while holding it with only my right hand, yet her sword phased through and cut right through both flesh and bone, separating my arm from my body from below the elbow.

"Fuckk, you stupid…. !!" I yelled in utter rage.

The pain was blinding. The shock of losing a limb was even greater. If not for total concentration and the pure, unbridled anger I felt, I would've passed out on the spot. I couldn't waste a single second, one moment of hesitation meant death.

Because we didn't clash swords, my blade remained in the same position while the demon was still following through with her attack, giving me an opportunity I couldn't ignore. 

I ignored the pain and adjusted the angle of my blade, bringing the tip from facing the ground to facing the ceiling and swung towards her head and arm.

'Striking tide.'

A water current followed every movement of my blade as it missed the demon's neck, but sliced her right arm clean off.

The blade fell from her amputated arm and landed on the ground a few feet away from her. 

"Look over there!" She pointed to a place behind me, in a borderline foolish attempt to distract me.

Seeing that her distraction failed, she turned her back on me and extended her left hand toward the blade on the floor, yet I swung up with my sword and cut off her arm.

Due to losing balance from the missing arms, she fell head first onto the wooden floor and slid for a bit before stopping. 

I didn't give her a chance to get up as I walked up to her, raised my sword over my head and swung down.

'Water wheel.' A current of water followed my sword as I swung vertically on the demon's head.

What I didn't notice was her spinning blue eyes already landing on another item. My sword struck her neck and separated her head from the shoulders it rested on.

'That was close. Her sword skills were lacking but those bullshit abilities made up for it and then some.' I mentally noted

I sighed and looked closer at the still intact corpse before me. 

'They're supposed to burn right?' I noticed no ash turning the demon's body into nothing.

As I stepped away, her head quickly reattached to her body as she stood up and backed away from me.

"I really am blessed!" She exclaimed as she stood up on her feet, her hands already regenerated.

"How??" I shouted in disbelief. "I cut your fucking head off." 

"Or so you think." She snickered, "I cut off my own head. With this." She pointed towards an empty spot right besides her shoulder. 

"It's invisible." She pointed out, seeing my confused expression.

'An invisible weapon? What now?' Now that the adrenaline was wearing off, the pain, desperation and frustration I was holding back hit me like a truck.

With a missing arm that I would never be able to regrow, my other arm stinging from the aftereffects of overload and an opponent with an invisible weapon, every hope that I had was lost. 

I had only ever fought 3 demons, and 2 of them brought me to the brink of death. The difference this time is that no one would come save me. I was still far too weak, and being weak was something that I simply could not accept.

"Say, you're pretty good. Better than any demon slayer I have faced so far." She said with a serious tone, her blue eyes wholly focused on analyzing every fiber of my being. "Join me, become a demon. You can be stronger, and you'll be able to re-grow that limb of yours." She added, pointing at my severed arm.

"If you stay human, even if you survive this somehow, your days as a slayer are over. You only have one arm and the other one isn't really that functional either."

"What do you mean?" I asked, panting heavily, blood still flowing from my severed arm. 

"Simple, I give you some of my blood, and you become the ultimate being. How fortunate you are." She smiled.

Her words hit deep. She was right, my days as a slayer were over. I didn't even become a proper demon slayer and my career already came to a close. Everything I worked so hard to achieve for all these years, the frustration and anger I felt, the blood sweat and tears I poured into getting stronger, everything would go to waste. Regardless of the outcome of this fight.

Her offer seemed like a blinding light at the end of a very, very dark tunnel. It was something I couldn't refuse. Afterall, becoming a demon would grant me the power I so deeply desired.

'Even if I become a demon, I could still hunt them. I'll just kill her after I become one. Simple as.' I thought. But the truth was different. I had been thinking of becoming a demon ever since I learned of their superior physical abilities, seeing one perform magic sealed the deal.

Seeing my resigned expression, the demon came closer to me with a wide smile on her face. Once she was right in front of me, she brought her hands over my head, the invisible sword moving towards her wrists to bathe me in her blood.

"Welcome, child." She announced as she closed her eyes, the sword closing in on her wrists. "Everything is going to be fine, you'll be one of u-" 

Her sentence was cut off by the sensation of cold steel ripping through flesh. Her head fell to the ground next to her feet a second later with a light thud.

"Huh?" She simply said.

Something within me snapped at that moment. I felt a deep disgust towards my own actions. Not because I considered becoming a demon, but because I ever considered rolling over and accepting a loss.

'If I die, I die. If I want to become a demon, I'll make a demon give me blood. I refuse to surrender myself like this.' I thought, as I gripped my sword with all the remaining strength I had left in my right hand and overloaded every single one of my blood vessels, performing the first form of water breathing. A strong current, capable of cutting right through stone, followed my blade as it cut through both her hands and head in one swift motion.

The next thing I knew, her head detached itself from her shoulders and rolled on the ground, still facing me.

The expression she made was worth all the pain I had to go through. Her eyebrows were raised, her deep blue eyes wide open in disbelief as her mouth struggled to form any words. 

"I won. Who's the fortunate one now huh?" I threw her a scornful look. Her expression quickly changed from surprise to anger. 

"How dare you! You stupid little shit! How dare you! I'll curse your ass and your lineage with misfortune you can't even begin to comprehend. You'll regr-" Her voice grew quieter and quieter as she began fading away.

My celebrations didn't even have the chance to start, as I looked at my missing arm and the blood leaking out, surprised at how I hadn't died yet. 

I took out some cloth from my sack and bandaged myself up as tightly as I could while sitting propped up against a wall.

'I guess this is it now. I'm done. Might as well go back, take over the business and live out the rest of my life in peace. I couldn't continue even if I wanted to anyway. If I live, that is." Without realizing, tears had started flowing out. 

This wound meant abandoning the one thing I was meant to do. This wound meant giving up on everything I worked so hard for. I had to give up now. Even if I continued, I wouldn't ever grow to my full potential. This thought tormented me endlessly, this would be something I would have to live with for the rest of my life.

Wiping my tears and slapping myself for being a bitch, I turned my gaze to my sack, reaching into it and grabbing the old man's books. Something which I'd practically given up my life to protect.

'These had better be worth it or else I'm tearing them up.' I thought while I cracked open one of them and read its contents.

The first book discussed, at length, thunder breathing. Everything from the boring philosophy, to its history and movements. Dozens of pages were dedicated to improving the initial movements, and dozens of others were dedicated to describing new forms.

Despite the book being hundreds of times better than what I learned water breathing from, I found it completely useless. Thunder breathing sounded even more unsuitable for me. 

The second book was more of the same. A book dedicated to total concentration and its effects on the body. Having a 21st century understanding of biology, this book was also completely useless. An entirely new breathing style dubbed lighting breathing took up the rest of the pages.

I was about to rip the books to pieces when a piece of loose paper slipped out of the second book.

The note that fell out read: 

"You didn't think that was it did you? There's a map on the back. Good luck." 

I did as instructed and looked at the map. It was drawn in the style of a pirate's treasure map that you'd see on a children's cartoon. 

"HNGGHHHHHH" I groaned.

Still, with no other hope, this was everything I had to rely on. My arm may not come back, but maybe I can get something else.