Whats the element of the p1 ninja you use? Get that then. If not, Torune next.

Minato? since he gives extra speed aka initiative during battle (max rank would give +400 speed)

or maybe Kotetsu for the increased chase damage if u like (max rank would give +50% chase increase)

honestly idk what attribute ninjas you're using, so i gave something that might help in general :)

I was thinking about torune and minato but I couldn't really decide between the two

Torune is better. In the grand scale of things, 500 initiative isn't all that useful compared to 30% more damage. Minato is only worth it if you're in a tight race for initiative within your server cluster. There are tons of immune ninjas and again, its better for you to get the elemental ninja cards before you get Minato. (IE if you use Minato a lot, get the Temari card)

Update: I ended up getting torune

Just a question, does the 30% more dmg still count even after supressing immunity or no?

Last I checked was No, 30% more dmg don't count after suppressing immunity.