As Rei and his party descended toward the forest's outer edge, the adventurers naturally spotted them.
At first, they raised their weapons, assuming a new enemy had appeared — an understandable reaction.
With an earthquake and the sudden cessation of monster movements occurring in quick succession, asking adventurers not to be on guard would have been unreasonable.
But once they recognized Rei riding Set and Vihera clinging to his front leg, they breathed sighs of relief and returned to attacking the monsters.
Some, sensing something off about the monsters' behavior, had already distanced themselves from the creatures.
In any case, Rei descended to the ground and headed straight for Marina.
"Rei, you're safe. Set and Vihera too."
With the monsters no longer moving, there was no need for Marina to issue commands anymore.
Perhaps anticipating that something had happened, Marina first showed a joyful expression toward Rei and Vihera, but in the next moment, her gaze turned faintly suspicious before she spoke.
"Hey, Rei, Vihera. I'll ask just in case... it's safe to assume you two are responsible for this monster situation, right?"
"Yeah. There's no doubt we're the cause."
"Wait, why am I included? In this case, Rei alone is the cause, isn't he?"
Vihera, having listened to the exchange between Rei and Marina, complained with clear dissatisfaction.
But her frustration was understandable.
After all, Rei was the only one who had fought the root puppet suspected of causing this incident.
Feeling aggrieved by the implication, Vihera looked at Marina and spoke.
"The one who caused this incident was something like an avatar of the Treant Forest. But Rei was the only one who made contact with it. Set and I just fought the Treants near the avatar, so it has nothing to do with us."
"...Well, we'll get into the details later. An avatar of the Treant Forest? That's who was behind this incident?"
Rei hesitated over how to answer Marina, who had asked while brushing off Vihera's protest.
Naturally, the researchers stationed a short distance away were also straining their ears, determined not to miss a single word Rei said.
The Treant Forest was a special place in many regards.
That alone made Rei's testimony about encountering an avatar of the Treant Forest something they could not afford to overlook.
The reason they didn't swarm Rei was that they understood upsetting him would be problematic in more ways than one.
In particular, the alchemists among the researchers had experienced what happened when a merchant had persistently pressured Rei — disgusted by the incident, Rei had temporarily left Gilm, making gryphon materials extremely difficult to obtain.
The others were either residents of Gilm or people with deep ties to the city.
They naturally knew what kind of personality Rei had, so rather than pressing him themselves, they adopted a stance of simply listening to his account for now.
"Avatar... that's probably the right way to put it. Yeah, that's right. I was able to communicate with the avatar of the Treant Forest. ...Was able to? I wonder. Rather than communication, it's more accurate to say its will was forcibly poured into me through images, I think."
"...Hm? What exactly do you mean by that?"
"Well, first of all, there's an existence in the Treant Forest that could be called the will of the forest itself. And in the central part of the forest, there was a terminal of that will... if I were to put it in Vihera's words, a puppet made of the avatar's wooden roots."
At the words "puppet made of wooden roots," Marina wore an expression of understanding.
For the will of an entity like the Treant Forest, a puppet made of plants was not strange at all.
Prompted by Marina to continue, Rei began to speak, recalling what had happened.
"Considering it was sitting on a throne also made of wooden roots, it probably wanted to make contact with us somehow."
At those words, the researchers' eyes sparkled with curiosity as they directed intense gazes at Rei — so powerful one might think they were exerting physical pressure.
"And so it poured images into you?"
"Yeah, I'll provisionally call it an image language for now. What was conveyed through that image language was that it prioritized spreading itself... this Treant Forest, above all else. No, it was the only thing it was thinking about."
"...I see."
So that was the reason the Treant Forest had been expanding by as much as ten meters every day.
Marina wore an expression of understanding at Rei's words.
The researchers looked like they wanted to ask many more questions, but they decided that for now they should listen to Rei's explanation and then bombard him with questions afterward, so they fell silent.
"So I told it that if it wanted to expand, it should head toward uninhabited areas like Gilm or Abuelo. No, to be precise, I didn't tell it so much as strongly projected the thought through image language. In the first place, the reason we came to the Treant Forest like this is because it was expanding toward Gilm."
"Wait, please!"
Among those listening to Rei's explanation, Thresha was naturally present.
And beside Thresha was Luno.
(Ah, they were safe.)
Seeing the two acquaintances looking unharmed, Rei felt slightly relieved.
Luno aside, Thresha lacked both the rank and ability to take on this quest.
She had only managed to participate by forming a party with Luno.
That was why it wouldn't have been surprising for Thresha to be the first to die...
(It must have been thanks to Luno's support.)
When Rei shifted his gaze from Thresha to Luno, Luno gave a small nod as he received it.
"Rei-san! Are you listening?! Why would you say such a thing about leaving the Treant Forest alone!"
As Rei and Luno exchanged glances, Thresha, unable to contain herself at the sight, shouted.
But what Rei returned to Thresha was a sigh.
"Listen, okay? I'm sorry and sad that your party member died in this forest. But you... you became adventurers prepared for death, didn't you? Isn't dying in this Treant Forest the same as being killed by monsters or bandits on a quest?"
"That's..."
Thresha, who had been angry at Rei's words until seconds ago, could say nothing more.
It was common knowledge that being an adventurer was a dangerous profession.
Expecting that only they would be spared from danger was impossible.
Thresha probably understood that, but she hadn't truly grasped it.
"Rei, that's enough about Thresha. The topic right now is the avatar of the Treant Forest. ...Why was it expanding toward Gilm?"
Rei, who had been talking with Thresha, nodded at Marina's words and resumed his explanation.
"The Treant Forest was heading toward Gilm because it understood that there were many beings with strong mana in Gilm... in other words, that there were many who would serve as its nourishment."
"...I see. For a Treant Forest that prioritizes expanding above all else, the more beings with mana who can serve as nourishment, the better, right?"
There was some surprise on Marina's face, but nothing beyond that.
She had been confronting the Treant Forest — an entity that defied common sense in many ways — from the start.
Given that, being told it sought beings with high mana as nourishment was not something that would make Marina panic.
In the first place, even if it sought Gilm's residents as nourishment, whether they would permit that was an entirely separate matter.
"So, what did you do when facing something that was seeking Gilm's residents as nourishment, Rei? Don't tell me you accepted it?"
"Yeah. I told it to stop using image language, but... apparently that struck a nerve, and it came to a fight."
Even hearing Rei's words, no one was angry.
Naturally. Given the situation Rei described, if a fight hadn't broken out, it would have meant sacrificing Gilm's residents... including adventurers with high mana... to the Treant Forest.
Thinking of that, those listening to Rei's story naturally wanted to say he had done well.
The researchers too had some reservations about Rei's explanation, but even they wouldn't think of offering Gilm's residents as sacrifice.
Though there were some who thought it might be fine to offer criminals.
Feeling relieved about that, Rei went on to describe the battle.
"The avatar of the Treant Forest, naturally, wasn't alone. They were weaker than the one I contacted, but several avatars... puppets made of wooden roots appeared. Also, the Treants in the plaza area — much stronger than the ones here — attacked. ...I left those to Vihera and Set, though."
"Stronger Treants than the ones here?"
"Yeah. ...Let's see, would it be easier to understand if I described it as the difference between regular soldiers and royal guards?"
At Rei's words, those listening to the explanation, including Marina, nodded in understanding.
...Though several researchers wore subtle expressions.
Major nations like the Kingdom of Mireana and the Bestia Empire aside, some small countries in their vicinity, protected by larger powers and never facing attacks on their royalty, appointed third and fourth sons of nobles as royal guards.
Such individuals naturally wouldn't seriously train themselves, becoming royal guards in name only — the researchers had probably heard such stories.
In any case, that was irrelevant right now, so the researchers kept those thoughts to themselves.
"Sounds like quite strong Treants."
"Yes, they were actually considerably stronger than normal Treants? Strong enough to make you wonder if they were High-ranking Species or Rare Species."
Vihera answered Marina's words, but Rei, who had seen the sight of Treants being exploded from within by the Magic Impact Palm enhanced through her fusion with Unbris, couldn't honestly nod along.
Rather, Vihera had appeared to defeat the Treants with ease.
"Anyway, a fight broke out with those monsters, and even when I used the Death Scythe and such, since they were made of wooden roots, they'd reconnect immediately after being cut. ...So, since the surroundings were an open plaza and I figured there was no risk of the fire spreading, I used magic to burn them..."
Saying that much, Rei averted his gaze slightly, looking as though the words were difficult to say.
There was no mistaking that his magic had caused what happened next.
"...And? What happened?"
Prompted by Marina, Rei returned his gaze as though resigning himself.
"The avatar of the Treant Forest — the root puppet — I burned it all with my magic. But whether that was a considerable shock to them, or perhaps fear... I don't know the reason, but... anyway, an earthquake occurred."
"We detected that here too. Around the time that earthquake struck, the monsters suddenly stopped moving."
Marina said this while looking at the adventurers who were defeating the motionless monsters and gathering materials and Subjugation Proof Parts.
"Figured. I only learned that after coming here, but... probably every monster in the Treant Forest is motionless right now. Anyway, that's what happened — there was an earthquake, and the plaza we were in was swallowed whole by a fissure. So we rode Set and evacuated like this."
"Again, that's quite... no, never mind. That's enough."
In the first place, they had ended up fighting not a monster but an avatar of the Treant Forest itself.
Rather, it should be said that it was precisely because it was Rei that he was able to return alive.
If it had been an ordinary adventurer, they would certainly have been caught in the fissure Rei described and died.
"Then..."
The moment Marina was about to say something else... a massive tremor once again enveloped the surroundings.
It was a quake incomparable even to the one Rei had felt in the central part of the Treant Forest.
What would the seismic intensity be? Rei still had enough composure to wonder, but for everyone else, such a tremor was something they were experiencing for the first time.
Even those who had been attacking the motionless monsters had no room for such things now. They could only crouch or sit on the ground, desperately enduring the shaking so as not to fall over.