I observed the building in front of me as I slowly approached the entrance.

The cult’s branch was located in a rural village and was disguised as a temple, while its main activities took place underground. They had managed to function without arousing much attention, and if not for their recent increased kidnappings I would have a hard time tracking them down like this. The money that I had poured into hiring skilled shinobi for following those traces helped as well.

The two-story building was devoid of people, apart from the two middle-aged man in robes standing on the second floor. They weren’t shinobi. They weren’t even strong enough to qualify as genin. They were to simply patrol the area. A wise choice. Sensor type shinobi could easily detect others’ chakra signature. This wasn’t a fire temple. A monk in a rural village with an unnatural chakra signature would only attract unnecessary attention and risk the chance of being exposed.

This should be easy.

Before the two could notice and alert others of my presence, I concentrated chakra into my legs and appeared behind them, knocking them out in quick succession.

I gave a signal and two shinobi appeared behind me. They were mercenaries that had been monitoring the temple. Not the strongest of bunch, but their forte lay elsewhere. In a sense, they led more ninja-like lifestyle than me.

“You know what to do. Contact me if anything’s up.”

They noded and transformed into the exact image of the cultists before hiding their bodies and taking their spot.

Going back to the first floor, I searched through the main room. It wasn’t hard to notice a hidden passage leading underground. The mercenaries' had done their job well enough.

The security of this place was laughable, or more accurately, non-existent. Apart from good enough cover, they had nothing else going for them. Not to mention, they were far too weak for the world domination that they were apparently aiming for.

It was clear I wouldn’t be getting any hearts with any remarkable potential from this place. I doubted even the cult leader was someone impressive. Though he should still be a jonin. It might be an alright substitute heart before I find something better.

In a way, this worked for me. I was here to get some expandable hearts to experiment with. Quantity over quality. One or two hearts would probably pop like a balloon, if not more.

I moved through the narrow hallway. The walls were decorated with strange ornaments and with torches mounted on the sides. There were few rooms along the way, though they all turned out empty so far after a quick inspection. But when I approached another door, a muffled scream caught my attention.

It was the voice of someone in pain and agony.

I opened the door after inserting the thread into the keyhole and breaking the lock. I took a step inside and glanced around at what appeared to be a small laboratory. In one corner of the room, there was an operation table, with an elderly man strapped onto it. Tears were pouring from his face and his screams were loud even while being gagged. I could see him desperately trying to fight against the restraints as his feeble strength continued to wane from the blood loss. Next to the table stood a middle-aged man in a dark robe with a cold expression, holding a scalpel and was dissecting the gagged victim without any regard.

Ensure your favorite authors get the support they deserve. Read this novel on Royal Road.

It wasn’t a pretty sight. Especially seeing the elderly man’s expression. It was clear that he was fully conscious during the process. It was pointless torture. It left a bad taste in my mouth.

The cultist frowned when the door opened.

“I don’t have time. What do you not understand when I said to not disturb me?! Unless it’s an emergency, warn me a day before instead of hastily organizing the meeting like this.” He said in an irritated tone without looking up.

I simply kneaded chakra into the threads.

Realizing that I was still in the room, the man sighed and raised his head.

“Leave. Don’t make me repeat m-”

And froze when he couldn’t recognize me.

Before he could even make a move, he was constricted. Threads had wrapped around his body, not even allowing him to make any noise. I knocked him out before looking back towards the table.

The elderly man must be one of the civilians. But I could see no more people in the room. Not that it mattered to him. He was already at death’s door.

Looking at the man’s desperate eyes, I decided to end his meaningless suffering.

Closing the door and locking it using the threads just in case, I moved deeper into the underground building. And not long after, I came to a stop in front of a larger door.

I could hear the sound of people arguing about something from the other side.

There were around two dozen people inside. There wasn’t any strong chakra signature that I could detect among them. The strongest of them was just at the level of a chunin. And aside from the few others, rest were too weak to even be considered genins.

Though chasing all of them down would be annoying.

Concentrating on the masks, the skin on my back began wriggling, followed by the two thread puppets detaching from me. They stood up next to me after their form finished morphing, their statues towering over me. I moved to open the door.

It was a relatively large room. A round table was placed in the center with the two dozen people sitting around it, fiercely discussing something. But the moment my presence was noticed, the silence descended in the room. Everyone glanced at me, their eyes quickly widening after spotting the two large creatures next to me.

Before most could even react, a wave of threads shot out and entangled the ones closer to the entrance.

The puppets went for the cultists in the far end.

The strongest cultist that appeared to be the branch leader finally managed to snap himself out of the panic and grabbed something from the pouch attached to his waist.

The man had grabbed what appeared a small vial storing some sort of dark creature that was mix between a snake and a centipede. Then he impaled himself with it.

The creature wriggled inside the cultist’s neck, but instead of pain, what the man seemed to have felt was more akin to euphoria. The dark snake connected with the man’s chakra system, causing his chakra to fluctuate before sharply increasing in intensity. His veins bulged, his fingers grew into claws, and tusks popped out of his mouth. His skin turned grey, and strange patterns appeared on his body.

If I had to measure his strength now, it would be around the level of a special jonin. It might not sound much, but the difference in strength was considerably large. To the point that current him could effortlessly wipe the floor with his previous self.

Nevertheless to say, it piqued my interest.

After the transformation was done, he tried to grab more vials and inject them into the three near him.

Great, the samples would be useful.

One of the puppets was already upon him. It grabbed his arm holding the vial and cut it off to safely secure the sample. The man showed no reaction to the pain. Losing an arm did cause him to become angry, however.

At this point, I had already got everyone in this room secured aside from the leader. If the man was alarmed of how outmatched everyone else was in this fight, he didn’t show. He instead tried to charge at me, ignoring the tall thread puppet right beside him.

I stopped the puppet, interested in how much power could the man actually display.

I observed the man’s condition as I engaged in a brawl with him. Then I let the thread puppet act as a punching bag while I took a step back.

He wasn’t anything impressive, but it did give me some idea of how the drug worked. Aside from making the receiver stronger, it seemed to affect the mental state as well. The man had a high pain tolerance and good defense. While fighting aggressively, he appeared to have kept sanity intact, mostly at least. That said, there was no guarantee that the drug would work the same for everyone. I wanted to learn more about it.

Thankfully, I had all of those wonderful volunteers that were gracefully sprawled on the floor, shaking in excitement for their turn.