you have to figure out that yourself, hidan can be lured to damage himself to a very low hp, while you cancel kakuzu's mega man blast and lower his life at the same time after hidan cast his mastery skill. the next round should give you a chance to finish off kakuzu and the 2 mobs infront. this is coming from a free player with 14k power(not 14.1 above). honestly, after i kill kakuzu and the 2 mobs infront hidan cast his mastery skill again and basically kill my ninjas and himself but actually got me the victory which is quite funny.

you seem quite cashed enough for a 13.8k power, but anyway congrats. im at 14k now and so far haven't focused on 80 yet, only managed to kill karin and jugo the last time so far but maybe ill try figuring it out again when i get a free time. im MB and free playing so i don't have much ninjas to choose from right now :/ i think i'm at 28 sub recruit ninjas right now and 10 summons to play with, *s lol.

i am at exam 80 fyi, and i'm free playing. it is easier to do exam when you are chashed enough, your mission list is visible and it tells how cashed you are right now. your sub summon quest must be bugged i guess since you said you have 11 but it shows in the quest that you have 14 already.