what does this Ippon Dadara want ?! (near save point at Nagatacho)

[Miesmann - allkeyshop]

he keeps saying : now is not the time..

https://ibb.co/THGkyM4

[A.K.T.]

Your current navigator is plot-locked to your character. Progress the main story for a while and you'll eventually get to swap navigators again.

[Sishiya]

IIRC, he becomes one of the optional demon assistants that follows around and digs up treasure/fights; but this only opens up later in the story. Keep following the story; you'll know when the option becomes available because your current assistant (don't recall the exact name offhand) will leave.

Optional assistants will then be shown on the map as green demon icons.

[Miesmann - allkeyshop]

i see, thank you : )