From an ethical standpoint, it would involve capturing one member of the Senju Clan and one from the Uchiha Clan and having them conceive a child.
To see if the descendant would awaken the Rinnegan?
Orochimaru was suddenly startled: "Is Madara having Ryou and Tsunade marry because he wants them to give birth to a descendant with the Rinnegan?"
Tobirama nodded: "It's possible. Madara already supports the world within Genjutsu; there's no need for Tsunade and Ryou to marry in reality."
"He definitely has a purpose for doing this, and that purpose might be for a second pair of Rinnegan."
It was a simple logic: Madara had already placed the construction of the world into a dream, so he no longer cared about anything in reality.
Having Tsunade and Ryou marry would deepen their connection to reality, making Ryou even more opposed to Madara's Eye of the Moon Plan.
This clearly wasn't out of Madara's kindness.
It's possible Madara already knew that the union of Senju and Uchiha would produce the Rinnegan, so he was pursuing a second pair of Rinnegan.
Tobirama snorted: "That old man, his schemes are truly grand! However, Ryou and Tsunade's child must have the surname Senju."
"The second pair of Rinnegan can only belong to Konoha!"
Tobirama then looked at Orochimaru solemnly: "Orochimaru, tell Monkey to pay close attention to Tsunade's pregnancy. Once the child is born, send out all the elites to take the child back."
"Yes, yes, yes, I will definitely tell teacher to have him pay attention to Tsunade's pregnancy status."
Orochimaru said this, but sneered in his heart. He couldn't seize Madara's Rinnegan, but could he not take the Rinnegan of a newborn baby?
When the time came, he would just snatch the baby. By performing body transferon it, he would become the second Madara, the third Sage of Six Paths.
This was a great opportunity!
Orochimaru spoke again: "Besides natural birth, has the Second Hokage considered the simplest and most direct method?"
Tobirama's phoenix eyes released a murderous intent as he looked at Orochimaru: "Orochimaru, if you dare to entertain that idea, I will kill you!"
The simplest and most direct method was cell fusion—having a member of the Uchiha Clan fuse with Senju Clan cells, or vice versa.
This was the reason Tobirama had been unwilling to say it before; human cell fusion belonged to human experimentation.
Humanity's understanding of cells was basically complete in observation but not fully understood; the specific functions of a large number of genes were unknown, and the regulatory networks between genes had not yet been clarified.
Cells are the foundation of human composition; no matter what kind of fusion experiment it is, there are risks.
Furthermore, it involved using his own clansmen for experiments.
Tobirama could dissect the corpses of the Uchiha Clan because the Senju Clan and Uchiha Clan had been mortal enemies since ancient times.
And Tobirama only used dead corpses, not living people.
Because he was benevolent!
But if it involved the people of the Senju Clan or the villagers of Konoha Village, that was a slippery slope he wouldn't touch!
Tobirama was curious about all unknowns, but he always held onto his bottom line.
He had both good and evil; he was a synthesis of the Third Hokage and Danzo.
Orochimaru smiled awkwardly: "Second Hokage, if I were to conduct human experiments, I would only use members of the Uchiha Clan to fuse with Senju Clan cells."
"I would not touch the people of the Senju Clan or the villagers of Konoha."
"..."
Tobirama went silent for a moment before simply offering a reminder: "Remember, use the Uchiha hawks!"
"Yes!"
Orochimaru then speculated: "Second Hokage, I believe this kind of fusion between Senju and Uchiha would have limitations!"
"It's impossible for two people from those clans who aren't even Shinobi to unlock the Rinnegan once their bloodlines fuse."
Tobirama nodded: "You have a point. Over a thousand years of reproduction, the bloodlines of many members of the Uchiha and Senju have degraded; most have even degraded into civilians."
Among the thousands of Uchiha clansmen, there were only two hundred Shinobi; the ratio of civilians to Shinobi was 5:1.
And this was even with the Uchiha practicing endogamy.
Among these Shinobi, bloodline grades could be differentiated based on the ratio of those who awakened the Sharingan.
Civilians were the Dalit untouchables, Shinobi who hadn't opened their eyes were Shudras, one-tomoe were Vaishyas, two-tomoe were Kshatriyas, and three tomoe were Brahmins.
The hierarchy was strict, with an orderly sense of status.
If the three tomoe were Brahmins, then the Mangekyo were deities.
Madara's Mangekyo was a Mangekyo that would never go blind; his bloodline was already close to the ancestor of the Uchiha Clan, the legendary god indra.
Hashirama's bloodline was even more noble, directly surpassing the Senju Clan's ancestor, Asura.
Only when the Yin and Yang of two people whose bloodlines approached the Sage of Six Paths merged would there be a chance to awaken the legendary Six Paths Eyes that governed the reincarnation of the three realms.
As a result, Tobirama and Orochimaru became skeptical of their previous theory that Madara wanted Tsunade and Ryou to marry for this purpose.
Orochimaru said: "Tsunade's bloodline is considered the strongest of this generation's Senju Clan. If I may be blunt, Second Hokage, aside from Tsunade, the rest of the Senju Clan are all mediocre people."
In the Warring States Period, as long as the Senju Clan took on a mission, the Uchiha Clan would take on a rival mission.
The two clans were evenly matched in strength.
But by the Hidden Village era, the Uchiha Clan produced genius after genius, while the Senju Clan was so mediocre they couldn't even make a splash.
Furthermore, they had very little presence; even the creator god Kishimoto only added their settings later.
This led many to believe that the Senju Clan had been dismantled by the First or Second Hokage.
Thinking carefully, would the First and Second Hokage be so bored as to cut off the thousand-year heritage of the Senju of the Forest?
Hearing Orochimaru speak of the Senju Clan's mediocrity, Tobirama sighed: "I knew this day would come. Aside from their advantage in Taijutsu, the Senju Clan's greatest strength was their endless stream of Ninjutsu."
"But for the sake of the Village, I made all the Secret Techniques of the Senju Clan public by putting them into the scroll of seals, which led to the Senju Clan losing their advantage."
In the Warring States Period, the Senju Clan's capital to compete with the Uchiha was their powerful bodies and Ninjutsu.
The Senju Clan was a clan of techniques; the Ninjutsu and Forbidden Jutsu in Konoha's scroll of seals were basically all heirlooms of the Senju Clan.
Shadow Clone, Flying Thunder God, Edo Tensei, Bringer-of-Darkness Technique...
They were all techniques of the Senju Clan.
In order to make the Village strong as quickly as possible and to give more civilian Shinobi Ninjutsu to learn, Tobirama made the family's techniques public property in the scroll of seals.
In this way, the base of Shinobi who could learn high-level Ninjutsu increased exponentially, and more people mastered high-level Ninjutsu and Forbidden Jutsu.
For example, Minato's Flying Thunder God, Yuhi Shinku's Genjutsu...
It gave civilian Shinobi opportunities and improved the Village's combat power.
But as everyone mastered more high-level Ninjutsu, the Senju Clan's advantage in techniques was leveled out.
Relying solely on Taijutsu, the Senju Clan held no real advantage.
To some extent, it was Tobirama who made the Senju Clan mediocre.
Hearing Tobirama's words, Orochimaru felt extreme pity that Tobirama was bound by boring things like the Village and the Will of Fire.
Otherwise, with Tobirama's talent, he could have definitely forged a unique path.
For instance, immortality—Tobirama had already researched the Pure Land thoroughly; could he not have solved immortality?
He still had ethics, he was still bound by secular concepts, and he wasn't thorough enough.
In his heart, Orochimaru pitied Tobirama, while simultaneously feeling self-satisfied.
So what if Tobirama had a brain? His vision still couldn't compare to Orochimaru, who could discard everything.