Izuna knew Tobirama in their past lives, their past life they lived in another universe, now here they were, sent back to another world of another universe.

He walks down the halls, his black bag on his back. He had math class for his first period, the same class as Tobirama's. They'll have to make use of this new life they were given, and use it to their advantages and enjoy it for as long as they can.