Both time-traveled characters ended up as villainous henchmen.

In the conventional understanding of the Naruto world, only Yang Release chakra has the ability to heal injuries.

However, under the power sharing effect of the Black Mist Space, he now possesses a powerful self-healing ability through the special Yin Release from He Nian of Demon Slayer.

However, this special Yin-style healing ability also has its side effects.

The self-healing ability comes from the demon, and so do the side effects.

Izumi Nen suddenly felt a desire to devour human flesh and blood.

Although this desire is weak and can be completely suppressed by willpower, it still exists nonetheless.

Therefore, Izumi Nen speculated that once his Yin Release chakra for healing his injuries was exhausted, the way he would replenish it would certainly be different from ordinary chakra recovery.

It is highly likely that he needs to devour flesh and blood to restore this Yin Release chakra.

"It's numb. It feels like a pure side effect."

Izumi Nen sighed and rubbed his forehead, feeling troubled. "Wait, could it be that the demon's greatest weakness has also been shared?"

Izumi Nen raised an eyebrow, immediately got out of bed, went to the desk by the window, and looked out at the bright sunshine.

He swallowed hard, then carefully extended one index finger, exposing it to the sunlight.

Warm, slightly scorching.

After waiting for a while, and seeing that the worst-case scenario did not occur, and feeling no discomfort whatsoever, Izumi Nen breathed a sigh of relief.

"It seems that the immortality of demons has been completely integrated into Yin Release, and their weakness to sunlight will correspondingly be transformed into... Yang Release?"

Izumi Nen pulled out a chair, sat down at the desk, took out a kunai, and made a cut on his left index finger.

Crimson blood slowly flowed from his fingertips, and at the same time, a realization dawned on him: if he wanted, he could now mobilize the Yin Release chakra within his body to instantly heal the wound on his fingertips.

However, he is not testing the self-healing effect right now.

Izumi suppressed the unusual movement of Yin Release chakra within his body, gathering it only at his fingertips and not directly healing the wound.

At the same time, he quickly mobilized his Yang Release chakra, gathered it at the fingertips of his right hand, and slowly aimed it at his bleeding left hand.

In an instant, the special Yin Release chakra gathered at the tip of his left index finger met with a devastating defeat.

This special Yin Release chakra is completely unable to resist the restraint brought by Yang Release chakra, even if it is personally refined by him and originates from the same source.

Moreover, the restraining effect is extremely obvious. If we compare it by quantity, one part of Yang Release chakra can offset three parts of special Yin Release chakra.

"They look like ghosts who've seen the sun..."

After the test, Izumi Nen was somewhat speechless.

The self-healing speed of demons in Demon Slayer is practically a bug in the ninja world where everyone is incredibly fragile.

However, this side effect, which can be easily suppressed by Yang Release chakra, greatly limits Izumi Nen's performance.

"We must find a way to eliminate these side effects."

Izumi Nen rubbed his temples and put away his kunai. "It seems the next research topic has been decided."

After saying that, he took out a piece of white paper and wrote down a few large characters:

The control and improvement of special Yin escape techniques.

To improve the side effects of this special Yin Release technique in his body, we must first understand all the characteristics of this special Yin Release technique.

Fortunately, Orochimaru's laboratory had complete facilities that could help him quickly understand the characteristics of this Yin Release chakra.

Especially when he also knows the general direction of its characteristics.

Moreover, Orochimaru had just left Konoha for a high-level mission, leaving him alone in the laboratory. This allowed him to be more unrestrained during experiments, without having to worry about hiding anything anymore.

Stretching, Izumi leaned back in her chair, looking at the bright and clean room around her, and gradually relaxed.

After officially joining Orochimaru's side, he moved out of his original small house and moved directly into Orochimaru's laboratory.

Although Orochimaru was very strict with him regarding his research on the Sage Body, he did not lack any living necessities.

Furthermore, due to Orochimaru's influence, after graduating from the Ninja Academy, he did not join the team that trained Jonin like other Genin and begin to accumulate experience by performing D-rank missions such as finding cats and dogs and cleaning up garbage. He only needed to complete the scientific research assistance work assigned by Orochimaru on a regular basis.

Of course, his powerful learning talent, which was the culmination of several versions of himself from different worlds, also played a significant role in this.

More importantly, his Sage Body gave Orochimaru great inspiration, and some research projects that had previously reached a dead end began to turn around.

Orochimaru seems to be working on a new type of cursed seal lately.

Unfortunately, Orochimaru kept a close eye on this, and Izumi Nen couldn't get any first-hand experimental data. He could only pass the time with the basic knowledge of sealing techniques that Orochimaru gave him.

After sorting out his thoughts on the special Yin Release experiment, Izumi Nen got up and left the room, heading towards the laboratory.

As I passed by the freezer storing ninja blood, I casually took two test tubes of the blood.

The demons in Demon Slayer need to consume human flesh and blood to maintain their powerful self-healing abilities.

Izumi Nen was unwilling to do so, so he had to settle for second best and use blood.

About three hours later, the preliminary results of the experiment became available.

Izumi Nen looked at the Yin Release chakra data listed on the report, his expression subtle.

"Its activity far exceeds that of ordinary Yin Release chakra, its energy efficiency is more than twice that of ordinary Yin Release chakra of the same volume, and it has an extremely strong affinity for blood."

In contrast, Yin Release chakra has a much weaker influence on the ninja's spirit and is less likely to cause psychological harm.

In the ninja system, Yin Release is strongly linked to spiritual energy. Ninjas with strong Yin Release abilities often possess extraordinary mental fortitude.

For example, the Uchiha clan and the Nara clan.

The former was madness beyond the average person, while the latter was also extraordinary in his strategies and tactics.

However, the Yin Release on Izumi Nen's body was not like that. Its greatest impact was on the physical body and blood, while its effect on the spirit was not as strong as that of a normal Yin Release, being about one-third weaker.

However, the mind and body are inherently connected, so dwelling on this is not very meaningful.

The project that Izumi Nen was most concerned about, namely the efficiency and effect of special Yin Release on the absorption of ninja blood, basically met his expectations.

He can absorb other people's blood either orally or by releasing Yin Release chakra.

The absorbed blood does not directly enter his bloodstream. Instead, it is absorbed and assimilated by Yin Release chakra and stored in his blood. When needed, it flows to the wound and heals it directly.

However, the absorption and conversion rate depends on the quality of the blood. The conversion rate is higher for powerful ninjas and much lower for ordinary genin.

After absorbing blood, his craving for fresh blood food intensified.

Although his Yin Release has a lower impact on the mind than ordinary Yin Release, it is still mostly a negative effect.

This must be resolved as soon as possible.

Izumi Nen put away the Yin Release chakra test report and carefully hid it away.

This thing must not be discovered by Orochimaru, otherwise who knows what terrifying things that guy might come up with.

"Let's start by practicing Yin Release ninjutsu and try to completely control the Yin Release chakra within our bodies."

Izumi Nen murmured to himself. He remembered that among the ninjutsu materials that Orochimaru had shown him, there were quite a few low-level genjutsu, and it seemed that even the Nara clan's shadow-type secret techniques were recorded to some extent.

Perhaps we could start from these aspects and develop a blood-based Yin Release ninjutsu that belongs to him.