I hesitated for a moment, and the bully knocked the tube out of the girl's hand. This piece of information is worth more than their lives. This is a ticket to get them out of this miserable abyss and go to another, less miserable abyss.

I was going to use a microphone to distract them for a while. The pipes slammed into the stone wall next to the alley. Spinro's seal was broken.

What did I do?

The Grey Spikes gruddely grabbed her. She screamed helplessly. There was a struggle, a flash of the knife, and then ...... Blood.

The smell ignited my anger.

The reservoir behind me began to pump the medicine. I lost control.

A roar pierced the darkness.

"It's him! howling ghost!" I rushed into the empty field as soon as one of the Grey Spikes shouted, trying to target the thug. I slashed him down, and the walls of the alley burst into a red mist. He was scattered on the gravel road.

Where's that girl? I lost her in the confusion. Enemy on the belly and back. The blade grinded against me, the shadowless claws, tearing indiscriminately, the bones and armor breaking together.

I tasted blood. There is more blood.

I saw her. A Grey Spike Gang was on top of her head, knife in hand. I can stop him.

But the machine pumped again, and my limbs were infused with strength.

Red clouds churned in my mind. Everything is blurred. I don't remember anything.

Everything is blood.

I don't know if I saved the girl. I don't know if I killed her. I'm still gnawing at the flesh, and the surviving Grey Spikes have fled into the darkness.

I turned around and chased them into the night. I had no choice.

They're the monsters I'm going to hunt. And I'm one of them.

A puddle of leaking venom flowed down the cracks in the alchemy technology facility into the trench area of Zu'an, and accumulated into a puddle in an isolated pit in the depths. Despite his humble origins, Zach has grown from a cloud of obscure slime to a thinking entity that inhabits the city's pipes, making occasional appearances to help the helpless, or repairing various public facilities in Zaun.

The first to spot Zach were a group of Zaan's children. They were playing in the puddle in the ditch when they noticed that some stones had been thrown back. As a result, this "return pool" spread among the residents of Zu'an Digou, and finally attracted the attention of an alchemy technology cabal. Despite the objections of the local population, the group of alchemists pumped out the liquid from the pool and put it in a bucket and brought it back to their laboratory.

The alchemists devised various experiments to test the effects of negative and positive stimuli, and they found that there was a gelatinous mass in the pool, which seemed to have some kind of spiritual tendency. Simply put, it mimics the type of stimuli it receives. If it is affectionate and friendly, it will respond with childlike joy and playfulness, but if it is inflicted pain and irritation, the alchemists will have to sacrifice a large number of prosthetic-enhanced trench scavengers to deal with the destructive reactions that follow.

Most alchemists thought that these reactions were mere nerve reflexes, but two of them weren't quite sure. They questioned the ethics of these experiments, as if the purpose of the experiments was solely to create an incredibly aggressive creature. The two conducted an in-depth investigation and found that the entire project was funded by Saito Takeda. He is a hot-tempered alchemy baron who is notorious for his bloody gang fights. The clue is clear: Takeda wants to develop a fighter who is not afraid of death, with a shapeable body, pervasive, and obedient. They also discovered the project's true name, the Zuan Amorphous Combat Body, abbreviated as ZAC.

The two begin to think about what to do, during which time they discover that the glue is not only a mimicry of a response to irritants. They observed autonomous behavior when not receiving obvious stimuli – very similar to sentient organisms. They referred to the creature simply as Zach, and assumed that the behavior he exhibited indicated that he was a thinking and sentient entity. They reported their findings to the head of the research team, but the stilt-like officer ignored their concerns.

Unwilling to give up, the duo began to carry out their own covert operations, trying to counteract the violent teachings given by the other team members. They wanted Zach to tell the difference between right and wrong, so they let him experience first-hand self-sacrifice and generosity. Their efforts paid off, with Zach saddened when he saw the researcher hurt his hand, and upset when he saw another researcher kill a rat in the lab. Eventually, the two of them had enough of the brutal experiments that other alchemists had done on Zack.

That night, which coincided with Zaun's Evolution Day memorial, the lab was empty, and they took the opportunity to dump Zach into a waste tank cart and drag him to a remote corner of Zaun. Their actions were soon revealed, and Baron Takeda's soldiers began a search. But Zaun was big enough for the two researchers to get out of the limelight. They had considered releasing Zach into the wild, but Zach didn't want to be released because he already considered the two researchers his family. The two of them are the only ones in the world who are good to him, so he wants to learn more from them. In fact, the duo was extremely pleased with Zach's reaction, as they also liked Zach and even regarded him as their adopted son.

In order to evade Takeda's men, they changed their identities and appearances, and settled in remote trench areas, away from surveillance and spying. Zach learned to mimic their voices, and soon learned to morph his own colloidal clumps into the organs needed to make sounds. He lived with his adoptive parents for many years, hiding in a pool of ditches or in a crack in a rock wall when necessary. Zack's "parents" told him about the world he lived in, telling him that there was a beautiful, magnificent side to the world. They took him to watch the moonrise at the Gate of the Sun, the rainbow on the stained-glass canopy of the Zuan Exchange, and the bustling and vibrant beauty of the city center. They also tell him that there is a cruel and harsh side to the world, and that Zach begins to understand that sometimes people can become vicious, ruthless, resentful, and prejudiced. Zach rejects this behavior and helps his parents as much as he can, using his skills to benefit the surrounding residents while trying not to attract unwanted attention.