They were inside the room that served as the knights' guardhouse. The sight of a door other than the one they had used to enter—and the way the knight's eyes had instinctively darted toward it when asked about Mercurio’s whereabouts—made the answer obvious.
"Siance."
"Yes."
With that single word, she grasped her superior's intent and brought a knife-hand strike down on the neck of the knight who was still conscious.
Casting a brief look of contempt at the unconscious man, Siance moved to join her superior at the door. Her disdain likely stemmed from the conversation they had overheard before storming the room.
The other subordinates Theoreme had brought along felt much the same. Scornful smirks played on their lips as they finished binding the unconscious knights. The man who had been the first to lose consciousness was already bound hand and foot, left rolling on the floor, unable to move even if he woke.
Less than two minutes had passed since they breached the room. The suppression of the two knights had been completed with staggering efficiency. Once the team gathered around Theoreme in front of the door, one of them handed him the key taken from the guards.
There was no need to ask what it unlocked.
"...Hm?"
As Theoreme took the key, his gaze suddenly shifted back toward the entrance they had first used. Siance alone understood the meaning of the gesture and gave a small nod.
"The ground shook."
"Do you think it was Lady Vihera?"
"Likely. No... definitely."
"Then a massive commotion must be underway out there. Someone might come here to investigate. We should hurry."
The team nodded at Theoreme’s command. One of the subordinates spoke up.
"Lord Theoreme, this man and I will stay here as a precaution. We need someone to handle anyone who comes to check on the guardhouse."
"Eh? Me too? Well, fine by me."
The man suddenly drafted for guard duty looked bewildered for a second before nodding. It was true that they needed to secure the perimeter. It would be a disaster if, after finally retrieving the imprisoned Mercurio, they walked straight into an ambush of knights and soldiers waiting just outside the door.
Understanding the logic, Theoreme nodded. "I'm counting on you. Secure this area until Prince Mercurio is out."
"Yes, sir!"
With their acknowledgment, Theoreme left the two men behind and inserted the key into the door’s lock. A sharp click signaled it was open. He pushed it inward, but what lay beyond was not a room, but a corridor. At the far end stood another door.
(I see. A double-layered security measure to prevent escape.)
Theoreme’s face twisted in displeasure at the realization of how thoroughly his master had been trapped. However, the thought that his beloved lord was just beyond that final door allowed him to push the irritation aside. He led Siance, Kyuken, and the remaining subordinates down the passage.
They reached the door at the end a minute later. It was also locked, but the same key worked. Theoreme exchanged a silent look with Siance. They shared a small nod, and he reached for the handle.
"My, I thought it was far too early for a meal... Is that you, Theoreme?"
In the room beyond, a young man who looked to be in his late teens or early twenties sat on a sofa, looking up from a book. His facial features and hair color bore a striking resemblance to Vihera’s—hardly surprising, as they were full siblings—but the impression he gave was entirely different.
Where Vihera was flamboyant and aggressive, the figure before them was the picture of tranquility. If she was Vihera of Motion, he was Mercurio of Stillness. A light of deep intelligence shone in his eyes as a faint smile touched his lips, his gaze fixing on the general.
It might have been an odd way to describe a prince, but if Vihera was a large-petaled rose, then Mercurio was like a flower that blended into a garden yet never lost its distinct presence.
"Prince Mercurio..."
Theoreme found himself unable to say more. The man before him was the one he had longed to see—the one to whom he had sworn his absolute loyalty.
"It seems you have gone to quite a lot of trouble."
"No... More importantly, I am relieved beyond words to see Your Highness safe."
"In my case, even though I was under house arrest, I was able to spend my time reading in peace. One might even say it was a needed rest. If anything, you and the others must have suffered far more because of my situation."
"As long as Your Highness is safe, no hardship is too great."
For a moment, the air was peaceful, belying the fact that they were deep within enemy territory. However, a voice broke through the reunion of master and servant.
"Prince Mercurio, Lord Theoreme, I apologize, but we cannot stay here. We must escape this place immediately."
Snapped back to reality by Siance’s words, Theoreme nodded.
"Prince Mercurio, Lady Vihera is currently causing a rampage to serve as a diversion. While their attention is elsewhere, we must leave the castle."
"...Sister is?"
The news was clearly a shock. Mercurio’s eyes widened to an extent that seemed impossible given his previous composure.
"I was under the impression that she had fled the country..."
"Yes. I took the liberty of seeking her assistance to rescue you."
"...I see. So you involved her. I had thought it might be best to simply rot away here."
"Your Highness."
Theoreme spoke in a reproachful tone, but Mercurio simply nodded before the general could say more.
"I know. I merely thought for a moment that if I stayed here, I wouldn't have to face the prospect of fighting my own family. Very well... let us go."
Mercurio stood up from the sofa. There was no tension in his movements; he was so relaxed it was hard to believe he was about to flee a castle that had become his prison. It was a testament to his absolute trust in Theoreme and his subordinates.
As they walked back through the corridor, Mercurio spoke.
"What is the plan?"
"First, we exit the castle. Once we are clear, Lady Vihera will cease her diversion and escape as well. Then, we flee the Imperial Capital and link up with the allied army."
"...I see. So a civil war is truly inevitable."
A shadow of grief crossed Mercurio’s face, but he immediately composed himself and looked back at Theoreme. In that moment, he truly looked like royalty.
"And what of our military strength?"
"We have the Third Prince Faction's forces and the nobles Lady Vihera brought over. Furthermore..."
Theoreme hesitated, causing Mercurio to tilt his head curiously. They reached the knights' waiting area, and the two subordinates left there immediately knelt before the prince.
"Please, do not be so formal. It is I who owe you my life."
"No, Your Highness. We are simply glad you are safe."
With a gentle smile, Mercurio reached out and touched the shoulder of the kneeling man.
"I am proud to have such capable, brave, and sincere knights serving me. Now, stand up. Escaping this place is more important than celebrating our reunion."
"Yes, sir!"
Mercurio smiled at them, but his gaze then shifted to the two knights bound on the floor—his former jailers. They had likely been knocked out only minutes ago, but they were already regaining consciousness, a sign of their elite training.
"I won't forget you two either," Mercurio said.
A soft smile remained on his lips, but his eyes flashed with a sharpness that wasn't there before.
"Mmph! Mmghgh!"
"Mngh, mmgh!"
The knights groaned behind their gags. Mercurio looked away as if he had lost interest. Theoreme signaled with his eyes, and a subordinate brought down a knife-hand strike on each of their necks, silencing them once more.
"Our conversation was interrupted," Mercurio noted. "What was that about our forces?"
Theoreme continued, ignoring the unconscious knights entirely.
"Yes. To be honest, when I found Lady Vihera, I had an unexpected reunion with a certain individual and managed to secure his cooperation. Additionally, while not a direct combatant, Margrave Larkus of the Kingdom of Mireana has promised his support and is currently present in the capital."
At the mention of the Kingdom of Mireana, Mercurio stopped dead. His gaze turned toward Theoreme, tinged with a sudden edge.
"You sought the cooperation of the Kingdom of Mireana for an internal conflict of the Bestia Empire?"
"I apologize. Our forces alone were simply not enough. Rescuing you was one thing, but a full-scale civil war is another."
Theoreme trailed off and shook his head. Mercurio let out a small sigh, accepting the reality of the situation. He knew that as the Third Prince, he lacked the numbers to win on his own.
"And who is this individual you brought in?"
"The man who achieved the greatest feat in the Spring War and triggered the defeat of the Bestia Empire. Surely you know of him?"
The news caught Mercurio off guard. He looked at Theoreme in disbelief.
"You don't mean... Crimson?"
"I do."
"...How on earth did you get him on our side? We were enemies in the Spring War."
"That is..."
Just as Theoreme started to explain, the door burst open. A woman of aggressive beauty with a brilliant smile appeared. Dressed in translucent clothing that looked more appropriate for a dancer or a prostitute, she locked eyes with Mercurio and beamed like a large flower in bloom.
"Mercurio! You're safe!"
Vihera rushed forward and pulled her brother into a crushing hug. Mercurio, for his part, was frozen. The reason was obvious.
"S-Sister?! What in the world are you wearing?!"
Having been buried in his sister's generous chest, Mercurio managed to pull away and shout.
"Oh, what a greeting. This is a reunion after so long, isn't it? Can't you be a little more excited?"
Vihera laughed, brushing off his concerns. Mercurio looked like he had a mountain of questions about her personality shift, but he realized this wasn't the time. He let out a sigh.
"I have things to say about your clothes... I have many, many things to say, but we'll talk about that later. More importantly, I heard you were acting as a diversion?"
"Yes. But I thought it best to regroup. I was given information on exactly where you were being held, so I came straight here."
"...And they just gave it to you?"
"Oh, yes. Once I started shredding their armor with my gauntlet claws, they became very honest."
The team collectively thought that "honest" wasn't the right word, but before anyone could speak, another person arrived.
"Lady Vihera, about fifteen soldiers and knights are heading this way. What are your orders?"
Tilleul Bugle showed his face at the door. Since his sister was here, Mercurio wasn't surprised to see her devoted follower. He looked back at Vihera and saw an expression of pure, predatory joy. She was practically vibrating with the anticipation of combat.
"Theoreme, there's no point talking to her now," Mercurio said. "We'll just have to break through the front."
"Agreed."
Vihera gave her brother a sidelong glance that made even him shiver before she sauntered out of the room. As Mercurio watched her go, he spoke with a tone of resignation.
"So, tell me. Why is Crimson helping us?"
Theoreme hesitated for a second, but he knew the truth would come out eventually.
"One reason is the magic items offered as a reward. And... well, it's a bit awkward to say, but it seems Lady Vihera and Crimson... Rei... have something of a not-so-ordinary relationship."
"...What?"
At his trusted confidant's words, Mercurio came to a dead stop.