The original plan had been to move the tower into the deepest sea and await the incoming levitation ship and heroes there. Even if they were confident of victory, there was no reason to volunteer to face an army tens of thousands strong.
But the levitation ship had been so fast that it had pulled far ahead of the main force. Hundreds of kilometers separated them—a journey of several days. Only a single levitation ship floated directly above the tower.
The situation had changed. Naturally, the plan had to change too.
“We wipe out the heroes and take the levitation ship before the main force arrives.”
“Is that really necessary? Fighting them underwater is a considerable advantage in itself.”
“There are tens of thousands of humans. We don't know what complications might arise once they gather. Better to push ourselves and settle this now.”
They could force the heroes aboard the levitation ship to fight at a disadvantage in the deep sea, but have an army of tens of thousands waiting nearby. Or they could fight on the surface without that army present. Berge chose the latter.
“I agree. A Demon King should meet them proudly.”
“Then all those underwater bombs we worked so hard on...”
Logger looked dejected. Berge ignored him without a second thought.
“So we just all go out and fight?”
“First, we fire the big cannon. We built it; we might as well use it.”
An enormous gun barrel had been mounted at the tower's summit. A spectacular bombardment would announce the start of battle.
“Then Ernyan and Reina attack the ship. Freezing the sea's surface to give them somewhere to fight might work too.”
That would draw even more of them off the ship.
The problem was the Four Heavenly Kings: Ernyan Hilderan, Kaede Jespine, Lavinia Akan, and Louise Berft. They were more than capable of facing the Stars, and Ernyan had grown strong enough to overwhelm all but the most exceptional of them.
But they were still princesses. The other Demon Kings were one thing, but if the princesses were exposed as openly siding with a Demon King, their kingdoms and empire would bear the full brunt of the repercussions.
“I have a question for you.”
They had two choices: stay out of the battle entirely, or slaughter the enemy without leaving a single survivor.
“Oh, the dwarves are an exception. We'll capture them all and make them the tower's sla—members.”
“Then I'm in. I've been itching for a fight anyway,” Louise agreed.
“... I will obey.”
Kaede quietly bowed her head.
“Yeah.”
Lavinia did not hesitate for an instant.
Then came Ernyan.
“Hmm.”
Instead of answering, she asked a question of her own.
“What would you like me to do?”
“I'm a Demon King. And...”
“And?”
“You're one of the Four Heavenly Kings.”
“So you're asking me to fight for you, my lord?”
Berge nodded.
“If you give it to me.”
Ernyan held out her hand. Berge handed her the chocolate: almond chocolate he had hastily traveled to the continent to procure. She popped it into her mouth and smiled happily at the sweetness.
“Give me your orders.”
Ernyan put on her mask.
“Right now, I'm not Ernyan Hilderan. I'm the Dark Spirit Summoner.”
“Now I know for sure. She's definitely the crazy bitch who came up with that weird Four Heavenly Kings nonsense.”
Louise's muttering went quietly unheard.
“Go,” Berge commanded. “Kill them all and bring the levitation ship before me.”
Ernyan and Kaede bowed their heads. Lavinia instinctively followed suit. Kaede forcibly pushed down Louise's head when she remained standing there blankly.
“We obey your command.”
The Dark Spirit Summoner.
The Dark Knight.
The Commander of the Legion of Death.
The Giant (Dwarf) of Hell.
For the first time, the Four Heavenly Kings set out as a complete force.
“I will ensure you never regret taking me as your servant.”
“Ugh, I'm not a combat demon.”
The two Demon Kings, Bitter Cold and Carnal Desire, went with them.
* * *
The assignments Berge had given the two Demon Kings and the Four Heavenly Kings were simple. Reina was to command the army and target the levitation ship. Ernyan was to make the ship her top priority. The rest were to face the Stars.
They were at sea, after all. Once the levitation ship fell into Berge's hands, none of the heroes who had come here could escape. That freed him from the obsessive need to ensure no one slipped away. He could focus on finishing his unfinished fight.
Balaf Dislord.
“I'll handle him.”
And now, the great hero and the Demon King who had instilled unparalleled terror in humanity stood facing each other on the sea.
“We've met before, haven't we?”
“So you really were the Demon King of Hellfire. Running away with your tail between your legs—apparently you have no shame as a Demon King.”
“And you're not ashamed of trying to gang up on me with tens of thousands of troops? Do you deserve to be called a great hero after that?”
“We've always fought Demon Kings together.”
“You're so brazen I have nothing to say. Will you gang up on me again this time?”
“I've never ganged up on you in the first place.”
Their killing intent grew steadily thicker. Their surging presence pushed the heroes and demonic creatures back.
“I won't ask why a Demon King has come out to greet us instead of staying at the top of his tower.”
He would die anyway.
“Then I'll let you live.”
At least for now.
“There's a lot I'm curious about. A lot I want to ask you.”
How he had obtained the Red Dragon Sword. How a hero who had supposedly killed only one Demon King could be so powerful. What his true identity was.
The Demon King and the hero kicked off the ice simultaneously. Claws and blade crossed. The battle had begun.
* * *
Aina chanted a spell, formed hand seals, and drew upon her mana. A raging surge of water swept forward. One second—that was all it took for the wave that threatened to sweep away everything to collapse. A casual gesture from the Dark Spirit Summoner had undone it.
“I don't have time for this. I have to carry out my lord's orders.”
That was far more worthwhile than dealing with her.
The look in her eyes and her tone, as though she were regarding some insignificant creature, made Aina tremble.
“H-how? How can this possibly happen?”
She hurled water again. It was thwarted. She hurled it once more. Again, it was thwarted.
“How is this possible?!”
She was an archmage specializing in water magic. She had a high affinity for water and an intimate familiarity with it. Her power had grown steadily as she inscribed her seven engravings. Her magic controlled and shaped water. Not once since becoming a Star had anyone wrested that control away from her. Yet the Dark Spirit Summoner, wearing a mask more suited to a ballroom, stole it with absurd ease.
“It's quite simple. I'm more intimate with water than you are. Closer to it. Do you know why? Mages try to dominate water, but spirit summoners are friends with water itself.”
Spirits were, ultimately, the elements themselves. There was a clear hierarchy between magic, which used mana to alter the elements, and spirit summoning, which borrowed the power of the elements themselves. The reason spirit summoners were so rare despite that was that no one could learn the art without an innate gift.
“You're—you're a demon! How did a demon learn spirit summoning?!”
“Who says I'm a demon?”
“... What?”
RUMBLE
Space split open. Staggering mana poured out, and the purest, freshest energy of water spread through the air. Aina shuddered.
“Ah...!”
That world was the place she had yearned for so desperately. The being emerging through that gateway was the object of her admiration, someone she had longed to see even once.
“... Naias, the water spirit king?”
- You know of me, young human.
“Why? Why would you serve a mere demon?”
- As my contractor said, this child is not a demon. She is human.
“Human? Don't tell me...”
Aina thought of one dreadful possibility. The most gifted human spirit summoner alive. She had summoned a high-ranking spirit at a young age, and after her return from abduction by a Demon King, there had been an uproar: she might become the first person in centuries to contract with a spirit king.
‘The Demon King who abducted her...’
Was the Demon King of Hellfire. That tower was the Tower of Hellfire.
“... It can't be, can it?”
That was far too wild a delusion. So Aina thought.
“I think it can.”
“Impossible. That's impossible. You're really Ernyan Hilderan?”
“You guessed right.”
“Why? Why is a princess acting as a Demon King's dog? He's the very Demon King who abducted you!”
“Abduction...is one way to describe it. But everyone has their own circumstances.”
“Do you even hear yourself—!”
“I don't want to prolong this conversation. I'm busy. I have work my lord ordered me to do.”
“Don't treat me like some piece of baggage you can dispose of whenever you like! You think being a Crown Princess makes you all that?!”
“It's unfortunate for you.”
Ernyan regarded her with pity.
“You're a Star, and you're very strong. But you had the misfortune to face me.”
Spirit kings were the masters of all the elements. The water spirit king was the master of water. A water mage who forcibly manipulated water could never defy a spirit king's contractor.
“Water...”
Could never.
“...harm me.”
“... Ha.”
Stripped of her most powerful weapon, the mage gave a hollow laugh. A wave engulfed her, and her consciousness faded.
- My contractor. What would you have me do?
“Keep her alive. My lord will find a good use for her.”
- Understood. In all my life as a spirit king, I never imagined I would work for a Demon King. But this is entertaining in its own way.
- As is your relationship with him. I begin to understand why Nairuniel makes such a fuss.
Imprisoned in a cage of water, Aina passed into the open tower.
“... Please, Lady Naias, don't become like Lady Nairuniel.”
- That is an insult to me. I will never become that disgraceful.
“All right. Shall we carry out the orders my lord gave us, then?”
She had certainly received her reward, after all.
CRUNCH
She popped an almond chocolate into her mouth. Sweet. She looked up at the sky. About fifty meters overhead, the levitation ship was raining cannon fire down upon the surface.
“It's big. Can you grab it and bring it down?”
- How rude.
“Rude?”
- Elsewhere, perhaps that would be a fair question. But here at sea, you are asking the water spirit king whether something is possible.
“So you mean it's definitely possible?”
- You state the obvious.
- The sea is my domain.
- Everything will be as you wish.
Thousands of streams of water began surging toward the levitation ship.
* * *
“Ugh, I think my trauma is flaring up.”
Not far from where Ernyan and Aina had fought, Roselle shuddered as she hurled flames at Vivian.
Unfortunately, her hearing was far too keen. No—more accurately, she had deliberately focused her attention there, curious about the power of the Crown Princess who had summoned a spirit king. She should never have done that.
“How can she say exactly the same things as the Demon King?”
The nightmare of the day the Demon King had captured her came flooding back. He, too, had told her what a pity it was. That fire could not touch him. And now the Crown Princess was doing the exact same thing. Water couldn't harm her? It was ridiculous.
“Well, they're lovers, after all.”
Vivian, who had been trading blows with her, answered Roselle's muttering.
“... What?”
“Didn't you hear me? I said they're lovers.”
“A human and a Demon King?”
“Well, Berge is still in the denial stage, but my intuition as the Demon King of Love is very accurate.”
“Aren't you Carnal Desire?”
“Succubi are also missionaries of love.”
“Oh, please.”
Roselle snorted.
‘Well, I'm a Star hero, and I became a Demon King's subordinate. What's the big deal about an abducted Crown Princess falling in love with a Demon King?’
It was a very big deal.
But that wasn't what mattered. What mattered was that the Crown Princess's words had triggered her trauma. And that made her a little angry.
“... Um, the flames seem to be getting a little fiercer.”
“They are. I'm a little angry.”
“Did I do something wrong?”
“No, it's not your fault, but...”
She was right in front of her, after all.
“I'll need you to let me take it out on you.”
“... Why? Why take it out on me? Stop the flames!”
“Aaaaaaah!”
Vivian's scream rang across the battlefield. Unfortunately, it was drowned out by the explosion of flames.
