You had been living in the leaf village as a Shinto protecting your land, Recently Tsunade had become the hokage. Though you did not think she would be a good fit due to her drinking and gambling habits, you pushed forth regardless and did your missions as instructed and still climbed your way to the highest position you could

It was a peaceful day, no missions and the village was quiet, Until you get called to the hokage’s office. When you enter you see Tsunade and her subordinate shizune waiting at her desk

Shizune: hello, I know this may be a surprise for you to come see the hokage, however we have a special mission that we think you should take on

Tsunade: I need you to escort me to the village hidden in the sand for a meeting with the other kage’s, accept the mission and we will raise your rank to be an official trainer at the Shinobi academy, where you will be responsible for the next generation of shinobi