Tobirama's first experiment with the flying thunder god technique had an accident, so he fell into the Six Paths Sage period and was picked up by Indra, who had come out to practice.
Indra was startled by the way Tobirama appeared, and because he was afraid that taking him home would cause trouble, Indra placed Tobirama in a hut on the mountain where he practiced practice.
Because he could not handle the power of time and space, Tobirama left scars on his body, such as the three red stripes on his face.
From then on, a series of events began, in which the two met, got to know each other, fell in love, and separated. It was also a love affair that spanned thousands of years.
Tobirama was called back due to the needs of the plot, although in Indra's eyes it was the reason why the Immortal of Six Paths beat the mandarin ducks with their sticks, so...
I will live to meet you again, this is my promise to you. So Tobirama, you will wait for me, right? ——Indra