The Slippery Tsunade

This is an exception for Tsunade. She's actually the older sister of his own classmate, Nawaki. As a reincarnator with foresight advantage, Toki naturally spared no effort to use the connection with Nawaki to actively build a relationship with Tsunade, one of the future legendary Sannin. At that time, Hiruzen Sarutobi was busy dealing with the outrageously prestigious Senju clan and Uzumaki clan. The situation of the Uchiha clan was not as dire as it is now, so Toki was still able to get along harmoniously with the villagers quite easily. So, Toki would often visit Tsunade's house under the pretext of being Nawaki's classmate.

Initially approaching with a purpose, Toki eventually regarded Nawaki as a friend. After all, as a normal person, everyone hoped to have a friend as straightforward and loyal as Nawaki. So Toki began attempting to change Nawaki's tragic fate. He utilized Nawaki's unwillingness to give up by forcing him to compete and learn trap techniques with him. He even risked exposure by privately telling Nawaki and Tsunade about Konoha's potential interest in Nawaki's lineage and the research on Wood Release. However, unfortunately, neither Toki, a newly graduated ordinary genin, nor Tsunade, a descendant of the declining Senju clan, had the power to confront the formidable Konoha elite at their peak.

Despite Nawaki surviving a supposed deadly explosive tag trap, he still fell victim to assassination, his organs hollowed out. It was also during that incident that Toki awakened his Sharingan with two tomoe, and, with the mental power accompanying his reincarnation, rapidly advanced to achieve the title of 'genius' second only to Kakashi with his three-tomoe Sharingan. It can be said that Toki owes Nawaki's death for his ability to survive from the Second Shinobi World War to the end of the Third Shinobi World War.

So, whether out of guilt or regret, Toki consciously or unconsciously took care of Tsunade due to his plot advantage, and Tsunade always regarded Toki as a younger brother, a source of emotional support. However, Toki knew that Tsunade was also on Hiruzen Sarutobi's list for removal, but thanks to Jiraiya and Orochimaru's protection, she escaped. Therefore, he worried that his butterfly effect might lead to Tsunade's death at the hands of Hiruzen Sarutobi during the Third Shinobi World War. So, using his knowledge of the plot, he prevented several situations where she should have fallen into life-threatening situations due to intelligence manipulation during the war. However, as Toki grew older, his body developed, and with several 'acts of kindness' towards Tsunade, her sisterly affection towards him began to change over time.

So, on a night after the end of the Second Shinobi World War, a night to remember Nawaki, the two, drunk, ignited like dry wood, staging a five-hour-long 'sibling' documentary. When they sobered up, Toki, feeling guilty, quickly put on his clothes and slipped away. One shouldn't eat grass by the burrow, especially considering Toki was still young at the time and had no intention of giving up the whole forest for a single tree. Furthermore, Tsunade had become one of the Legendary Sannin, enjoying the pinnacle of popularity in Konoha as the healing princess.

Toki, who was well aware of the darkness within Konoha, knew very well that if Tsunade became 'Uchiha Tsunade' with him, then the Konoha elite would mercilessly suffocate this 'established candidate for the Fourth Hokage' under their control. At that time, Toki didn't have any system, and his talent only barely qualified him to become a jounin, far from enough to confront the Konoha elite. So, for survival, Toki began to avoid Tsunade and intensified his efforts to create a scumbag image for himself by frequently changing girlfriends. However, secretly, he began to cultivate his own power, preparing to overthrow the useless Uchiha Fugaku and plotting to oppose Konoha.

As it turned out, Toki's actions were quite correct, as Tsunade, tormented by love, lost interest in becoming Hokage, leaving the highly esteemed Sakumo Hatake as an easy target for Danzo's manipulation and public pressure to commit suicide. Meanwhile, Hiruzen Sarutobi began grooming Minato Namikaze, planning to weaken the power of various ninja clans and elevate the Sarutobi clan as the foremost family in Konoha. Subsequently, just as in the plot, the major ninja clans suffered heavy losses during the Third Shinobi World War. Hiruzen Sarutobi, at the cost of the Hokage position, signed an unconditional peace treaty with Iwagakure, choking off the resources for the ninja clans to recover after the war. If not for Toki's intervention, the Sarutobi clan would have long become the foremost family in Konoha.

After the end of the Third Shinobi World War, Minato Namikaze was elected as the Fourth Hokage, and Tsunade, seeing only her dwindling Senju clan left, finally believed Toki's earlier claims that Konoha would turn against the Senju clan. With a heavy heart, she was the first to leave Konoha and embark on her journey as a wanderer. So, when Uchiha Toki took power, he ultimately chose to elevate Tsunade to the position of Hokage ahead of time, rather than pushing for Danzo, hoping to entice her to return to the village. After all, first love carries a unique buff for men. However, when Toki saw Tsunade again, his instinct was to slip away. Because whether their initial interactions were genuine or not, Toki, who had matured since then, didn't want to tie himself down to just one person after experiencing the vastness of the world.