Flashback

A conversation between the previous Hachibi jinchūriki and A.
Can B cope with living as a jinchūriki?
Didn’t the previous previous [jinchūriki] die because the seal failed?

The previous jinchūriki does.
Funeral.

A coup d’etat? is staged in Kumogakure.
A and B vs. several Kumogakure people.
B is brought down.

Shortly after:
Konoha (Minato) vs. Kumogakure (A & B)
A begins, exchanges blows with Minato.
B changes into his bijū form for a bit.
The Konoha army gets scared.
Konoha retreats.

Minato: “Quick, if you don’t recognise B , he’ll become neither jinchūriki nor human.”
He says only this before leaving.