The Hehuan Sect cultivates alchemy; my senior sister helps me refine alchemy throughout the world.

Gu Yunyan gritted her teeth.

"Fine, I'll trust you this time. But if you dare to try anything funny..."

"What tricks could I possibly be playing?" Shen Yifei shrugged. "I'm the most honest person I know. You're only at the early stage of Tribulation Transcending, while I'm only at the early stage of Nascent Soul Transformation. You could crush me with a single finger. What tricks could I possibly be playing?"

"Let's begin then." Gu Yunyan sat back in her chair, crossed her legs, and asked, "How do we do it?"

Shen Yifei looked around. "Right here?"

"What's wrong with the main hall? There's no one here."

"Master, it's best to keep dual cultivation a private matter. What if your subordinates come in and see you and me..."

"Who told you about dual cultivation?" Gu Yunyan interrupted him. "I just transferred my demonic energy to you, but we didn't actually cultivate together. Couldn't you have done it through our clothes?"

"It's inefficient through clothes. Think about it, the demonic energy comes out of the dantian, passes through the clothes, then through my clothes, and then into my dantian. At least 30% is lost along the way. Add in the back-and-forth transfer, and 50% is gone. You input ten portions of demonic energy, I get five, refine them and give them back to you, so I only get two and a half. Isn't that a waste?"

Gu Yunyan narrowed her eyes. "You've calculated things quite clearly."

"I'm an alchemist, and the heat and dosage must be precise. I need to know exactly how much is wasted."

Gu Yunyan stood up, took two steps on the stone slab, stopped, and looked back at him.

"Are you sure you don't have any other intentions?"

"Master, I am a simple-minded person. What other thoughts could I possibly have?"

Gu Yunyan snorted and turned to walk towards her bedchamber.

"Keep up."

Shen Yifei followed behind, while Liu Mengli laughed out loud inside the cauldron.

"Master, you're really something. You managed to get him into bed with just a few words."

"Am I lying? How did it feel to have her demonic energy running rampant inside me?"

"Once you've tricked her into stripping naked, I need to get a good look at what a female demon in the Tribulation Transcending stage looks like. That cleavage of hers is so deep, did she use some kind of method to squeeze it out!"

Gu Yunyan's bedroom was located at the back of the main hall, with a large bed in the center, covered with black silk quilts and pillows scattered about.

There was a bathtub in the corner of the room, and it was steaming.

"The Pavilion Master certainly knows how to enjoy himself." Shen Yifei glanced at the bathtub.

Gu Yunyan sat on the edge of the bed. "Come here."

Shen Yifei walked over and stood in front of her.

Gu Yunyan reached out and unbuckled her belt, causing her black dress to slip off her shoulders. She was wearing nothing underneath; her skin was radiantly white, and her chest rose and fell slightly.

Liu Mengli clicked her tongue in amazement, "Wow, that's truly spectacular!"

Gu Yunyan lay down on the bed, her long legs together, her bare feet resting on the edge of the bed.

Shen Yifei took off his clothes, lay down next to her, turned to his side, and placed his hand on her lower abdomen.

When Gu Yunyan saw Shen Yifei's body, she was so surprised that she couldn't close her mouth!

"You... what are you transformed from?"

"Master, I am endowed with extraordinary talent; please get used to it."

"What's this talk about getting used to or not? I don't need it anyway!"

Shen Yifei didn't say anything, thinking to himself that whether or not it would be useful was probably not up to him!

He turned to the side and placed his hand on her lower abdomen.

Gu Yunyan's abdomen was flat and smooth, with the outline of abdominal muscles visible beneath her skin, and it felt firm to the touch.

Shen Yifei pressed his palms together, and dark golden spiritual energy surged from his dantian, seeping into her body through his palms.

The moment the spiritual energy touched her dantian, the demonic energy within Gu Yunyan's body exploded like a cat whose tail had been stepped on. Black demonic energy surged out of her dantian, enveloping Shen Yifei's spiritual energy and swallowing it back.

Shen Yifei groaned, sweat beading on his forehead.

Gu Yunyan's demonic energy was far too strong; it was many times greater than that of someone in the Tribulation Transcending stage. His spiritual energy was like a drop of ink falling into the ocean, instantly submerged.

"Sect Master, could you please tone it down? Your demonic energy is too potent; it devours my spiritual energy as soon as it enters."

Gu Yunyan closed her eyes, and her demonic energy subsided somewhat.

Shen Yifei's spiritual energy finally gained a foothold in her dantian. The dark golden spiritual energy enveloped a wisp of demonic energy and slowly pulled it back.

The wisp of demonic energy was dragged out of Gu Yunyan's dantian and entered Shen Yifei's body through his meridians.

The icy sensation returned, much more intense than before. Last time it was two wisps, this time it was a large gush, like ice water being poured into his veins, making Shen Yifei shiver uncontrollably.

"If you can't take it, just say so." Gu Yunyan opened one eye.

"We can handle it."

Shen Yifei gritted his teeth and dragged that wisp of demonic energy into his dantian.

Dark golden spiritual energy surged in from all directions, enveloping the demonic essence. The spiritual energy spun like a millstone, crushing the impurities within the demonic essence bit by bit.

Black impurities were squeezed out of the demonic energy and expelled along Shen Yifei's meridians. A layer of black sweat seeped from his skin, smelling both fishy and foul.

This time, Shen Yifei transformed into Su Wuwang, his body covered in black impurities, turning him into a little black man.

The demonic energy circulated in the dantian, its color changing from pitch black to dark gray, then to light gray, and finally to translucent.

Seventy percent of the impurities were crushed, but the remaining thirty percent remained stubbornly embedded in the core of the demonic essence, and could not be crushed no matter what.

Shen Yifei opened his eyes. "Sect Master, the impurities in your Demonic Essence Core are too hard. My spiritual energy can't break them down."

"Being able to grind 70% is already quite good." Gu Yunyan sat up, looked at her arms which were covered in a lot of black sweat, and frowned. "This is much better than I expected."

"Let me first feed this wisp of demonic energy back to you, and you can see the effect."

Shen Yifei sent the refined demonic energy back into Gu Yunyan's body through her meridians.

As soon as the translucent demonic energy entered her dantian, Gu Yunyan's brows twitched.

"It's definitely different, much purer now!"

Suddenly, she felt as if she had been electrocuted, a tingling sensation spreading throughout her body.

She felt a little comfortable and wanted to hum a few times, but it would be too embarrassing to do so out loud.

Gu Yunyan bit her lip and swallowed the muffled groan. Her face remained expressionless, but the tips of her ears turned red.

Shen Yifei was close to her and saw the crimson blush; he knew what was going on.

"Master, how are you feeling?"

"It's alright." Gu Yunyan's voice was very steady. "There are indeed fewer impurities, and the circulation of demonic energy is smoother than before."

Shen Yifei tried to pry open her tense legs, but couldn't. It seemed she was still somewhat resistant!

Shen Yifei tightened his grip, and Gu Yunyan squeezed her legs even tighter, as if they were locked.

"Master, relax."

"Where are you putting your hands?" Gu Yunyan looked down and saw Shen Yifei's palm on her knee, his thumb rubbing against the inside of her thigh.

"Check the circulation of demonic energy. You just absorbed and refined demonic energy, so we need to check the flow rate in your meridians."

"Does the examination require touching the thigh?"

"There are many meridians in the legs, and the three Yin meridians of the foot all run through the legs. You are at the Tribulation Transcending stage, so the meridians in your legs are thicker than those of ordinary people. I have to feel them carefully, right?" Shen Yifei said seriously, without stopping his hand movements, pushing his thumb half an inch up from the inside of his knee.

Gu Yunyan grabbed his wrist.

That's all for today! How many more sessions will it take to get it clean?

"You are in the Tribulation Transcending stage, while I am only in the early stage of the Nascent Soul stage. It's like giving water with a small spoon; it will take at least half a year, if not three or four months."

"Does it take that long?"

"Sect Master, you have no idea how abundant the demonic energy within you is. I simply cannot dispose of it all."

Is there a faster way?

"Yes, one true dual cultivation session is enough for us!"