In The Dancing Of Fire, In The Curve Of Old Bones

Before his death, Tobirama created a safegaurd for the Village, a seal intended to bring him back if the Uchiha acted oddly. It seems that 'All but three of the Uchiha dying' was classified as suspicious by the seal. Which means Tobirama is back from the dead, stuck dealing with an emotional six-year-old. Tobirama wasn't meant to be a father, let alone to an Uchiha. [Slow-burn]