After reincarnation, the new "self" was formed through the physical body in the womb, so it would likewise be influenced by the genetic information inherited within it. For example, a healthy and robust baby might grow up to be more optimistic and outgoing, while a sickly and frail baby might become more pessimistic and introverted. But these were ultimately only influencing factors; emotions could not alter a person's fundamental nature.
The current fetus and Tenten's original body were essentially sisters born to the same father and mother. Their genes were extremely similar, so with the soul unchanged, the differences would be even smaller.
By the same logic, this method should produce roughly the same results for others. Among the Konoha 12, the one who would change the most was probably the future Naruto, but Nawaki had long since made preparations.
Once the fetus had fully taken shape, Nawaki quietly left the bedroom. The couple, under genjutsu, remained completely unaware of the entire process.
In the days that followed, Nawaki not only ordered the Anbu to protect the couple in secret, but also occasionally slipped in at night to check on the fetus's development, ensuring that Tenten could be born safely.
Before long, Nawaki received news that Hizashi Hyuga's wife was pregnant as well.
Because the Hyuga Clan's defenses were strict and the Byakugan's scouting abilities were exceptionally powerful, even Nawaki could not infiltrate the compound. He therefore could not handle things the same way he had with Tenten.
Fortunately, he had a good relationship with Hizashi. After receiving the information, he paid them a direct visit and, while acting as their guest, pretended to inadvertently discover that Hizashi's wife was pregnant.
Since Nawaki himself was highly skilled in Medical Ninjutsu, Hizashi and his wife had no doubts about his judgment