The Fūinjutsu Mishap

Tobirama was the best Fūinjutsu master of his time, but even he couldn't spot the little mistake in his new seal that, instead of bringing his beloved back to life, sent him into a new life. In a universe that isn't quite his own and still looks and feels like a spitting image of it, he finds himself stuck as the bijū of a newborn Uzumaki girl. No way back, only forwards.