Hashirama and Madara accidentally traveled through time and space, but were told by their contractor who claimed to be their previous life: If they want to return to their own world, they must accumulate the energy to help the protagonist in each world.
As a result, the two people who will never grow up began to travel through time and space, unknowingly showing off their affection while helping the protagonist.
Things to note:
1. Fate update
2. Many private devices
3. Poor writing
The first world - "Guarding Sweetheart"