That day, Tanjirou finished his morning training and, as usual, came to the ward to visit Himura Ruri.
Upon entering, he saw the young girl gritting her teeth, her forehead covered in fine cold sweat, her hands gripping the edge of the bed tightly.
She was struggling to stand and walk on her own, each step appearing precarious.
"Miss Ruri!" Tanjirou was startled and quickly ran over to support her.
"Your injuries haven't healed yet. How can you push yourself like this? Quickly, sit down and rest!"
He carefully helped her onto the wheelchair.
Himura Ruri leaned back in the wheelchair, breathing slightly, a faint, unnatural blush on her pale face from the recent exertion.
She looked up at Tanjirou, her large eyes filled with pleading and longing: "Brother Tanjirou… I… I beg you, please take me to see my father, okay?"
Tanjirou froze instantly, a troubled expression on his face.
He knew what state Himura Senichi was in. If Miss Ruri saw him in that berserk condition, wouldn't it be another huge blow to her?
"Miss Ruri, this… Himura Senichi, he is currently…"
Tanjirou stammered, unsure how to explain.
Just then, Cheng Mo pushed the door open and walked in, seemingly to check on Ruri's recovery.
He glanced at the scene in the room, his gaze falling on Ruri's pleading face and Tanjirou's troubled expression.
"Teacher…" Tanjirou looked as if he had seen a savior.
Cheng Mo didn't speak; he simply walked forward calmly and naturally took the wheelchair handles from Tanjirou's hands.
"Teacher?" Tanjirou was a little surprised.
"It's fine," Cheng Mo said indifferently, turning the wheelchair towards the door, "I'll take her."
Tanjirou looked at his teacher's calm back, and much of his worry inexplicably dissipated.
With his teacher present, nothing could possibly go wrong.
He quickly followed: "I'll go too!"
Cheng Mo pushed Ruri through the quiet corridors of the Butterfly Mansion and arrived at the outer perimeter of the special isolation ward.
Here, there was a specially made, reinforced glass observation window that allowed visibility from the outside in but not from the inside out, and it was equipped with a soundproofing barrier.
Only when a specific channel was activated externally could sound be transmitted unidirectionally.
Through the glass, Himura Senichi in the ward could be seen still restrained by special devices, with subtle electric arcs coiling around his body.
Most of the time, he remained in a berserk state, his face contorted in a grimace, roaring and struggling, hitting the restraint devices, emitting dull thuds.
"Father…!"
Ruri's tears instantly welled up, and she covered her mouth tightly with her hands to suppress her sobs.
Although she had mentally prepared herself, seeing her father in such a state with her own eyes pained her as if her heart were being cut by a knife.
Cheng Mo operated a control nearby, opening the unidirectional sound transmission channel.
"Father… it's me, Ruri…"
The girl's tearful voice trembled as it entered the ward.
"Can you hear me? Father…"
Something surprising happened.
The previously berserk and struggling Himura Senichi's movements suddenly froze the moment he heard his daughter's voice!
He stopped roaring and hitting, and stiffly turned his head.
Those crimson eyes, filled with confusion and hunger, stared blankly in the direction of the sound.
Though he could see nothing.
"…Ruri?" An extremely hoarse, distorted syllable, almost inhuman, was squeezed with difficulty from his throat.
"It's me, Father! It's me!"
Ruri, hearing the response, was overcome with tears of excitement.
She began to speak continuously into the microphone, recalling the bits and pieces of their past as father and daughter, the warm light in the tavern, and the delicious meals her father used to cook for her.
She even softly hummed an ancient, simple folk song that her father used to love the most.
Inside the ward, Himura Senichi completely quieted down.
He stood silently in the restraint device, head bowed, his cloudy tears mixing with saliva and dripping onto the floor.
On his contorted face, an extremely painful yet incredibly gentle, indescribably complex expression actually appeared.
Tanjirou watched this miraculous scene from the side, both moved and puzzled.
He couldn't help but quietly ask Cheng Mo beside him: "Teacher, I've seen many demons, like the Lower Moons, who seem to have their own consciousness, able to speak and think."
"Why is Himura Senichi still so… berserk after being transformed for so long? Only reacting to Miss Ruri's voice?"
Cheng Mo's gaze remained on the father and daughter in the ward, and he explained calmly: "Generally speaking, when a demon is first transformed, its consciousness is chaotic. It needs to consume human flesh and blood to gain power and begin its path of evolution."
"The more flesh and blood it devours, and the higher its quality, the faster its strength grows. In this process, it will also gradually recover more of its sanity."
He paused, his tone slightly cold: "However, this recovery is often accompanied by the permanent loss of memories from its human period and the complete annihilation of its humanity."
"The act of devouring itself constantly reinforces its identity as a 'demon,' ultimately turning it into a monster with intelligence that preys on humans."
"Himura Senichi's situation is special. His strong willpower and unique demon blood allow him to stubbornly resist this 'demonization' process, refusing to devour human flesh and blood to 'evolve.'
"Therefore, his power growth is slow, and the recovery of his sanity has reached a stalemate. He cannot completely demonize and regain reason by eating like ordinary demons, yet he struggles to maintain complete human consciousness due to the erosion of demon blood. That's why he exhibits this struggling state, sometimes berserk, sometimes with fragmented lucidity."
Tanjirou suddenly understood, nodding repeatedly, and looked at the now quiet figure in the ward, his eyes filled with deeper understanding and admiration.
So, Himura Senichi had been fighting the most difficult battle in this way all along.