Dungeon Battle Royale ~ Since I became a Demon King, I will aim for World Domination-Novel

“Izayoi-dono, is your spear also thirsting for blood on this fine night?”

“Hah… No need to ask. Each time I slay a foolish human, they become Shion-sama’s power…! Therefore I’m going to offer all humans to Shion-sama as nourishment!”

My friend who is protecting the Domain with me ― Izayoi-dono, is fond of the deep crimson I poured into his glas.

“However, Saburou-dono, I must say, this beverage ― tomato juice is truly magnificent.”

A noble vampire such as myself wishes to indulge in red wine, but unfortunately you won’t find any such within the Domain. As a last resort, I replaced the wine with the juice wrung out of the tomatoes grown by the humans Shion-sama captured.

――♪～

Hmm? A phone call?

Yataro-dono’s name is displayed on the smartphone.

“Saburou here. Do you require my strength somewhere?”

Most of the tasks I receive from Yataro-dono revolve around defense battles.

『Saburou, is Izayoi with you as well?』

“Indeed. Izayoi-dono is waiting on standby with me. So, which sector does require our help?”

『Ah, that’s not it. This time it’s something else. I’m sorry, but could you come to my room together with Izayoi?』

“As you wish.”

After I finish my call, Izayoi-dono asks me, “Was it Yataro-dono?”

“Yep.”

“Where are we supposed to go?”

“It seems to be a different matter this time.”

“Different matter…?”

“Quite so. For the time being, we’re supposed to visit Yataro-dono’s room.”

Izayoi-dono and I head to the 【Transfer Array】 that would bring us closest to Yataro-dono’s room.

◆

“Sorry for calling you all of a sudden.”

Once Izayoi-dono and I enter Yataro-dono’s room, he greets us with a gentle, old man smile.

“Don’t mind it. What kind of business do you have with us?”

“I wanted to introduce a new comrade to you.”

“A new comrade?”

“Hmm, rather than calling him your comrade, it’d be more correct to call him your pupil, I suppose. Shion asked me to raise him.”

“Shion-sama did?”

“Yeah. Come on, Setanta…say hello to them.”

The child standing next to Yataro-dono raises its hand with an innocent smile, “Okaaay! Nice to meet you! I’m Setanta!”

I see. This child is going to be my pupil, huh…? That’s Shion-sama for you. His eyes are discerning enough to see through my hidden ability ― my coaching skill! As expected, even if I want to hide my charisma, it’s still bound to fail!

“This child is an SSR subordinate. Shion-sama is also expecting a lot from his future.”

SSR? If I remember correctly, Kaede-chan is also an SSR. In short, he’s a very rare subordinate procured through 《Random Creation》. For me to be allowed to take care of such a precious subordinate…

“Well then, I’m going to entrust you with Setanta’s training ― Izayoi.”

“As long as it’s Shion-sama’s order, this humble servant shall bet his life to raise that person into a strong veteran fighter!”

――!?

Yataro-dono pushes Setanta’s back towards Izayoi-dono. Meanwhile Izayoi-dono has placed a hand on his chest and is looking up to the ceiling with an expression overflowing with deep emotions.

“Waaaaaaaiiit!”

“W-What’s wrong!?” Yataro-dono is confused by my soul’s scream.

“Yataro-dono…have you grown senile!?”

“How rude…”

“To my ears it sounded…as if you said that Izayoi-dono would become the boy’s teacher…”

“You didn’t mishear. Izayoi will be in charge of Setanta’s training.”

“Why…!? Why is that so…!?!”

“You see…Setanta’s favorite weapon seems to be the spear.”

“This is why old men…”

“You’re becoming quite rude…”

“Are you saying that you’ve forgotten my strongest weapon type!? Separs and rapiers both rely on thrusting attacks!”

I draw my beloved sword ― the Rapier of the Abyssmal HollowMithril Rapier, and adopt a thrusting stance.

“Don’t swing your weapon in my room!”

“No! I won’t stop until I get you to tell me a reason I can accept!”

I exhibit my splendid thrusting skills, all for the sake of making Yataro-dono realize my exquisite ability.

“It’s Shion! Shion has ordered me to leave the training to Izayoi!”

――!

…Shion-sama’s order?

I recall Shion-sama’s somewhat awkward manner of expressing his love ― the heat of his fire lances with my whole body.

“…Yataro-dono, haven’t you simply misunderstood what Shion-sama said?”

“Of course not! If you wish, you’re free to directly check with Shion!”

Checking this with Shion-sama, huh…? If what Yataro-dono says is true, Shion-sama’s hot love will probably scorch my body.

“Gununu.” I grit my teeth.

“Oh well, so be it. You will both train Setanta! Even Shion won’t be able to complain about this much leeway, right?”

“Truly…!?”

“Truly, it’s true! That’s why, put your sword away.”

“At once…!”

I sheathe my beloved sword, and shift my eyes to my new pupil.

“Boy! Our training is going to be strict!”

“We shall raise you to the strongest subordinate!”

“Okaaay! I’m looking forward to working with you!”

Absolutely no hesitation even after receiving Izayoi-dono’s and mine gazes, huh? He must be an outstanding talent.

“Listen up you two! You will teach him to stay safe first and foremost!”

“Leave it to us…! Let’s go then!”

“You are Shion-sama’s property. Death won’t be permitted, got it?”

“Okaaay!”

Izayoi-dono and I take Setanta with us, leaving Yataro-dono’s room.

◆

“Setanta, ready your spear!”

“Eeh? We’re not going to kill enemies?”

Setanta pouts unhappily after hearing Izayoi-dono’s instruction.

“Get ready!” When Izayoi-dono adds bloodthirst to his words, Setanta’s body trembles with a start, and he sets up his spear.

“Come at me with the intent to kill!”

“That’s fine? It won’t be my fault if you regret it later! ――《Wind Chase》!”

With an innocent smile on his face, Setanta charges at Izayoi-dono while his body is clad in wind.

“Yaaaaahh! ――《Flash Thrust》!”

Even though Setanta fires off a high-speed thrust, Izayoi-dono only comments, “Naive!”, and blows Setanta away with one sweep of his spear handle.

“Ugh!? I’m far from dooooonne!”

Setanta gets up right away, charges at Izayoi-dono once more, and unleashes one thrust after the other.

“I admit that you are fast…but! Your thrusts lack power!”

While Izayoi-dono continues to parry Setanta’s attacks, he blows Setanta back with his spear. Even though Setanta keeps charging afterwards as well, he only gets blown away over and over again, unable to damage Izayoi-dono at all.

“I see… It is still unrefined as a technique, but low-leveled humans should pose no threat, I think.” Izayoi-dono broods while looking down on Setanta who’s laying sprawled on the ground.

Going by my own analysis, Setanta possesses the same strength as a C-Rank monster. He’s more powerful than a newly created dhampir, but…he won’t be able to win against the invasion team’s bloodkin.

“…-rou-dono…Saburou-dono!”

“Mmh?”

“What do you think, Saburou-dono?” Izayoi-dono asks me.

What do I think…? About what? Let’s use my secret surekill-technique here ― giving a suitable, noncommittal confirmation.

“Uh-huh, I agree with you.”

“Would you be able to ask Yataro-dono if there aren’t any reasonably weak invaders around then?”

“Hmm? Reasonably weak invaders?”

“As opponents for Setanta.”

“Oh! Yeah! That was it!”

Finally getting an idea of what Izayoi-dono has been talking about, I call Yataro-dono. After learning that reasonable invaders are proceeding through the 7th sector, we decide to head over.

“The enemies number 12. Setanta, you remember the order in which to kill them?”

“I just need to start killing them from the weak-looking ones in the back, right?”

“To be precise, the weak-looking humans holding wands.”

“Okaaay!”

For some reason, Izayoi-dono acts very helpful. A major reason might be the order from Shion-sama, but he explains things quite carefully to Setanta. Hmm…at this rate, Izayoi-dono might monopolize the teacher position.

“Setanta, your movements are too straightforward. Anyone can immediately tell that you’re simply moving in a straight line, even if you do have speed. If you move left and right, you will be able to spice up your tempo. If you do this, you will be able to reach even further heights in skill.”

I inform Setanta of his flaws which I have felt from the earlier practice bouts between Izayoi-dono and him.

“Uuhh… I don’t quite understand such complicated stuff.”

“Then you might as well focus on copying me!”

“Oki…”

“Setanta! What Saburou-dono says is reasonable! Did you understand?”

“Yeees!”

Gununu, he disapproves of my opinion while readily agrees with Izayoi-dono. This is bad… a really bad situation… I have to come up with measures to sustain my dignity as his teacher…

“Found them! I’m off! ――《Wind Chase》!”

As soon as he spots the invaders, Setanta clads himself in wind and rushes off.

“――! Wait Setanta!”

Not having expected Setanta to charge all of a sudden, Izayoi-dono loses his usual calm, revealing a rare moment of panic.

“C-Child…?”

“Eh? Enemy――”

“Hello! And, bye bye! ――《Flash Thrust》!”

Setanta very swiftly thrusts his spear at the wand-holding female invader.

“It’s the enemy! Demon King!? The Demon King has come attacking!!”

“Kill him!”

“Surround him!”

Even while falling in panic because of Setanta’s sudden appearance whom the invaders misidentified as Demon King, they move to fence him in.

“Kuuh! The precious subordinate entrusted to us by Shion-sama…! Saburou-dono!”

“On it!”

Izayoi-dono and I begin attacking the invaders, slaying them one by one.

“Mine darkness, pierce through everything! ――《Dark Lance》!”

I stab a human, who’s shown me his back in order to surround Setanta, with a spear of darkness.

“――!?”

“――《Dark Night Tempest》!”

The storm of darkness unleashed by Izayoi-dono swallows the humans who’ve been preoccupied with Setanta.

“Enemy attack! …Demon King? Three Demon Kings!?”

“No! Those guys are kin!”

“W-Why…i-isn’t this domain a farm…?”

“Calm down…there’s only three enemies! We can survive this!”

Spotting Izayoi-dono and me, the invaders succumb to fear.

“Survive…? Hah, all your hope for survival was gone in the instant you encountered me! I shall be the one to show you true despair! You may curse your bad luck for having run into me! ――《Fast Thrust》!”

I close the distance in an instant, and unleash a quick thrust at a nearby invader. Without knowing about our feelings, Setanta brandishes his spear with an innocent smile, attacking the enemy rear guards. Izayoi-dono keeps firing magic from behind, making sure that the invaders won’t focus their attacks on Setanta.

These invaders are low-leveled. They’re weak opponents chosen to become Setanta’s training targets. If Izayoi-dono and I went at it for real, the invaders would drop like flies.

Pheeew…Setanta has escaped falling into a predicament, but it won’t be much of a training like this. As I sigh while defeating the human in front of me…

――!

Isn’t that invader over there raising his ax overhead, aiming at Setanta who’s fully absorbed with happily attacking the rear guards!?

“Setanta!”

“Kuuh! ――《Fast Thrust》!”

I can believe that one hit by that ax would kill Setanta, but I have no idea what Shion-sama will do to us if Setanta gets injured. I shorten the distance to the ax wielder with instantaneous movement, and stab my rapier at his nape.

“Seta! There’s more than one enemy! Keep watching your surroundings!”

After having gallantly rescued Setanta, I scold him.

“Okaaay!”

“Okaaay…not! A child that doesn’t understand the nature of battle won’t be allowed to stand on the battlefield! ――《Thousand Thrusts》!”

Because Setanta’s reply doesn’t show the slightest hint of him reflecting on anything, I unleash a flurry of thrusts at a nearby human while full of anger.

“Did you understand!?”

“Yes…I’m sorry…”

Overwhelmed by my force, Setanta finally shows some remorse. Afterwards, I clean up the 12 invaders while cooperating with Setanta, who has apparently become depressed, and Izayoi-dono.

“Umm…sorry…for just now…”

After receiving a harsh scolding from Izayoi-dono as well, Setanta has become as docile as a little puppy. His look strongly incites a strange feeling of paternity in me.

“Uh-huh, as long as you understand. I shall let you off the hook if you obey me from now on as your father…no, as your big brother. I shall think of you as my little brother as well, so I shall promise to raise you with great care!”

“Big brother…? Umm, Saburou-san, you’re my big brother?”

“Quite so! From now on you may call me onii-chan!”

I’ve been aware of my deep, hidden wish of gaining a little sister, but for there to also have existed a wish to have a little brother…

“O…anchan?”

――!

Once I look at Setanta as he calls me onii-chan with upturned eyes, I almost feel like a sealed door has been thrown open inside me.

“Yep, Seta. Let’s aim for new, distant heights together!”

“Oki! Onii-chan! We’ll grow strong together!”

That’s how I deepened my bonds with my new little brother ― Setanta.