story mission?

it's not a story mission

when u got that situation?

how ?

Heyyy, is that Mizuki?

That's the remaining and surviving members of Uchiha Clan, planning to engage a coup against the current Hokage ..

Jokes aside, no idea since as far as i remember, there's no story mission that spawns NPC like them ..

Its plot instances or story mission

u can see this it's no plot or anything else

It is a plot mission. Why don't you try and continue with the story. If you can't beat the current plot mission, then it will be like this.

Certain ninjas will appear as part of a plot mission - that includes the one you are seeing right now. Another example is when you start the game, you will see the 3rd Hokage at the top of the building as part of the plot mission.