Batwoman, holding the Trident of Poseidon and accompanied by the captured poisonous plant, led the group towards the large central tree.
"Do you want to know the secret of each personality construct? You think the method to solve this situation is hidden within them?" Charles asked.
"It's a very logical conclusion," Batman replied. "It's a simple and unsophisticated line of reasoning from an ordinary person, one without any psychic ability."
"What's so simple about it?" Charles muttered under his breath.
"Everything in this world occurs for a reason, even if they don't conform to the physical laws of the real world, they must follow the law of cause and effect," Batman said. "With a cause comes an effect, it's the most fundamental rule in the cosmos."
"Many things happen before they actually do. You see these personalities as the cause of some disaster, but in reality, they are the result of many earlier disasters."
"If you treat them as the cause, to prevent a disaster from happening, and try to snuff them out in their infancy, the true cause that created these personalities will continue to produce them incessantly, without an end."
Charles furrowed his brow deeply, Batman hit the nail on the head, the current most troublesome situation faced by The Mind Assault Squad was that killing these terrifying superpower user personalities was already extremely difficult, but according to David himself, these superpower users were still being generated ceaselessly within him.
No one knew where they came from or where they were going, no one knew how to completely eradicate them, nor did anyone know how to prevent David's psyche from generating these potentially disastrous personalities.
But Batman provided an enlightening perspective. The problem they needed to solve was not these personalities, but the deeper underlying factor that led to their creation.
After the poisonous cloud was dispersed, the journey became easier. Upon reaching the base of the tree, they found a small treehouse, with a spiral staircase hugging the trunk, reminiscent of the type of structure you'd expect to find at a Scout Summer Camp.
The moment Batman set foot on the staircase, he stopped and said, "It seems to be related to his childhood; this thing wasn't designed for adults."
Batwoman climbed up and nodded her head, her reasoning was the same as Batman's. There wasn't any profound reason, except that in addition to being narrow, the steps were also very dense, with almost no gaps in between.
For an adult, stepping on them meant half of the foot hung off the edge, and the step ahead was too close, so the heel of the front foot would bump into the back leg, which would be very awkward if one were to climb step by step.
But for younger children, this design was both easy to navigate and incredibly safe.
Two steps higher, approximately a meter off the ground, wooden bars were nailed to the tree to serve as handrails, with every detail suggesting the place was more a play structure than an actual treehouse meant for living.
They reached the top, where two small adjacent rooms with a platform in the middle were located. Batman bent slightly at the waist and, before actually stepping onto the platform where the rooms were situated, he observed traces on it.
Batwoman was also observing, while Charles watched them both, as he truly did not know what they were seeing.
The place was very ordinary; the platform was made of nailed and wired planks, the walls of the house were made of tree trunks, weeds, and mud, and it seemed that each time a new group of children came, the structure had to be rebuilt, likely as part of a summer camp activity.
"There are footprints," Batman pointed to the marks on the floor. "There appear to have been three children and one adult here; a heavier child standing at the top of the stairs, two thinner and smaller children in front of the room door, and that adult standing at the edge of the platform."
"Something happened..." Batwoman said with certainty, "Something must have happened here."
"So, what do you think happened at that time, Ms. MacTaggart?" Shiller tapped the end of his pen gently on the desk and looked at the woman sitting opposite him.
The woman had brown hair tied neatly behind her head and wore a white lab coat, giving the impression she had just left her workstation.
"I don't know, David never told me," the woman identified as MacTaggart appeared somewhat tired, and she said, "When that happened, he was still living with his parents. It took me a lot of effort to get a rough idea of what happened, but I don't know the specifics, he never told me."
"Then tell us what David did tell you, ma'am," Shiller said.
"Just call me Moira."
"Ms. Harrell, also known as the mother of Legion, when she brought him to Muir Island, he was very quiet, and we all thought he might have childhood anxiety disorder," Moira said.
"Although I was constantly researching his mutant ability at the time, I didn't forget to take care of his mental health. I thought it was inhumane to keep him in a ward all day, so I applied to take him out into the court yard for some air at noon."
"There was a large sycamore in the yard, from France, under which I liked to enjoy the shade, so I also took David there. But he didn't want to go near that tree, and even in hot weather that would make one sweat all over, he wouldn't stand in the shade."
"So I began to probe what this was all about, and he just kept shaking his head. Only after my relentless questioning and investigation did I learn that at the age of seven, at the summer camp to which his mother and stepfather sent him, there had been an accident."
"No one knows what exactly happened, but there was an activity in the camp where they led the Scouts on a jungle trek to identify plants, learn to make fire, and build treehouses."
"It was called jungle trekking, but it was really just leading the children through a small forest, teaching them to recognize a few common poisonous plants, and showing them how to start fires with flint. Everything was going well, and the children were having a great time."
"But something went wrong at the very last step. That day, the only instructor present fell from the platform of the treehouse he was building. I don't know how," Moira frowned slightly as she spoke.
"How high was it approximately?" Shiller asked.
"David said it was about two meters," Moira said, slightly furrowing her brow. "But the instructor sustained very serious injuries. I heard there was a problem with his spinal nerves, and he'll have to spend the rest of his life in bed."
Shiller also furrowed his brow.
Standing at the edge of the platform, Batman looked down and, not surprisingly, saw the shape of a person imprinted in the moist earth below.
"Someone fell down?" Charles asked.
Batman turned around, nodded, and said, "Yes, an adult fell down and landed here on the ground."
Charles walked over, glanced over the edge, and then realized that the place wasn't particularly high. He wouldn't dare to jump down, but if someone really did fall, it probably wouldn't be a big deal.
Batwoman suddenly shook her head and said, "They didn't fall by accident. They were pushed."
The two caped figures stood at two different spots. Suddenly, Batman reached out to grab Batwoman, who, as if frightened, shrunk back and hid inside the room behind her.
Batman rushed forward to the door, trying to drag Batwoman out, but Charles, understanding some of Batman's emotions, immediately rushed over from the edge of the platform, grabbed Batman's cape, and pulled him away.
The two of them tussled all the way to the edge of the platform. Batman, using his strength advantage, pinned Charles to the ground. But then, Charles kicked hard, flipped over, and Batman, caught off-balance, tumbled off the platform.
He landed precisely on the very spot with the human-shaped imprint, not a hair off.
"That's not scientific," Charles said. "If, as you said, the children here are only six or seven years old and the Scout instructors are all retired military personnel, how could a six- or seven-year-old child possibly throw a retired soldier off?"
Batman had climbed back up and said, "Couldn't you do it?"
Charles paused slightly.
"You mean this is actually David's experience? He used his mutant ability to push the instructor off the platform?"
Batman nodded and said, "And he probably severely injured the instructor with a special ability because if this were a normal fall, the soil below is quite soft, and the vast majority of adults would not be hurt by falling into it."
"But from the impression in the soil below, it seems the person couldn't move at all and lay here until the ambulance arrived."
Understanding seemed to dawn on Batwoman. She turned to the trapped toxic plant beside her and said, "I've heard that many personalities split from dissociative identity disorder are there to protect the main personality."
"For a 7-year-old to instantly immobilize an adult, aside from brainwave control like yours, the best approach would be to target the nerves, which is the same method we use," Batman said. "The nerves are a fatal weakness in the human body's ability to move."
"So this personality was born at that moment," Charles said, looking towards the toxic plant inside the bubble. "The story goes like this: David was seven when he attended a summer camp and, unfortunately, they ran into a terrible instructor."
"From the actions we just simulated, it is possible that the instructor intended to harm or sexually abuse another child. Indeed, this is a perfect crime scene. If it were in a remote enough community, no one would notice what was happening here, and the children wouldn't dare say anything."
"But David wasn't an ordinary child. He tried to stop the instructor, and after the instructor had pinned him down, his self-defense mechanism was activated, giving birth to a superpower user specialized in human nerves, who subdued the instructor and protected David."
"I think he would manifest in the form of a plant, perhaps because this place was supposed to protect them," Batwoman speculated. "Perhaps the instructor told them that in the perilous jungle, building a shelter out of plants was the best way to survive the long night."
"That's possible," Batman affirmed. "Children's thinking is very abstract, they focus more on association than logic. They may not understand the necessity of building a shelter, but they would definitely realize through such actions that trees and plants are their protectors."
"When someone tried to hurt them here, their first reaction might not be to call the police or seek help from an adult like an adult would but to imagine a Plant Deity coming to rescue them."
"That's why child psychology is considered a separate discipline. Because of incomplete brain development, insufficient education, and lack of common sense and rational thinking, their way of thinking is completely different from adults," Charles concluded.
Immediately making the connection, Charles said, "So in David's psychic battlefield, the less human-like, the more bizarre and absurd, the more likely they come from his childhood."
Batman nodded and said, "Regarding the Joker, maybe I was spot on. This plant personality, which looks like a tree person and dresses like the Joker, may not be because he's seen clowns at the circus or in movies."
"It might simply be because David learned to play cards for the first time in the Scout camp, and the person teaching him told him that the ace was the strongest card in the deck."