Just beaten ninja exam 75 with fire main (naruto 3*, zabuza mist hidden, Guy) at 13.4k power. Just share my team in case anyone need it. Main Skill (1,3,3,2,1 , summon: ninja cat)
naruto x x
zabuza Guy x
x main x

Rely a bit on rng where some of ur ninja crits, and the enemy didnt.

Round 1: Main use skills (pray that the ignition debuff is transferred to the one in front of main, so that your main can do a bit more damage to him, since only naruto and main does ninjutsu standard). Also pray that either zabuza or guy has crit or combo atk here

Ninja exam 80 for fire main

Strategy
This level is way easier than level 75 and the power required is way less too (I complete with 12.9k power, could be even less if you dont bother to max upgrade your Ino). Ninja used: Ino, Zabuza hidden mist (shikamaru works too), naruto 3*, Fire main. Skill used (sealing jutsu, feather illusion, clone or bani chakra (if it ignites suigetsu then it is perfect), genjutsu return and pet that supplement your combo)

x x x
x x Main
Ino Naruto Zabuza

Round 1: Sealing jutsu on Karin, followed by Ino's chase to chaos. (best if it succeeds to chaos). Ino's skill on Sasuke.(Must success, otherwise restart). Main sleeps Jugo, followed by Ino's chase to chaos.(best if it succeeds to chaos). If the chaos Karin or Jugo hits suigetsu, then you are one step closer to success. Pray that either Zabuza and naruto standard atk managed to kill off suigetsu, or if it didnt, pray that suigetsu didnt crit or combo on his standard atk. Restart if it does LOL coz he will just clear off the whole team with it. The chaos sasuke will also hit his own team twice, pray to rng that he helps with killing off suigetsu.

Round 2: Zabuza's water prison on Sasuke to stop his mystery. Naruto's skill on Jugo. Then standard atk to break Jugo's shield.

Round 3: Ino's chaos on Sasuke (must succeed here again, so RNG). Sasuke will then help with killing off his team. Finish off Jugo here.

Round 4: If you manage to get here, you should be almost done with it. Use Zabuza's mystery, Ino's chaos, Main's skill or sleeping in turn to control/chaos sasuke. And finally finish him off.

Not my own strategy, credit to some CN strategy website, I just help here with some translation and improvisation :) Good luck beating lvl 80 ^^
* Just a sidenote: I think this strategy (Ino's chaos/shikamaru/zabuza's water prison) could work for other main too, as long as you kill off suigetsu first, and manage to stop sasuke from using mystery.
This post was last edited by 106***@facebook at 2016-8-22 00:53

Ninja exam lvl 82:

Fire main 16.5k power
Team: Guy, Naruto, Neji
Main Skill: 3 3 3 1 1, summon: Gamachu
x x x
x x main
Guy Naruto Neji

Strategy:
I found this stage more achievable than lvl 81, with less dependent on RNG and lucks.

Round 1: Main's sealing jutsu on the big guy on top right, Neji's skill on the big guy on top left. With main using sleeping standard atk, the flute girl in the middle will be asleep throughout the fight, if you are lucky.

Round 2: Guy's skill on the big guy on bot right.

Round 3; Use rasengan. Use Neji's skill on the big guy on top right.

Round 4: use sealing jutsu on the big guy on top row. U can basically put on auto now. As long as ur main manage to sleep the middle girl for as many turn as possible, u can easily beat this stage.

PS: For ninja exam 81, I beat it with random luck and I dont remember the exact steps :). If u manage to get through it, feel free to use my formation for 82.

Ninja exam lvl 83:

Fire main 16.5k power
Team: Guy, Naruto, Neji
Main Skill: 3 3 3 1 1, summon: Gamachu

Guy Naruto Neji
x x x
x Main x

Strategy:
Key for this stage: Take down the girl with flute first.

Round 1: I use Neji's skill on the * top row instead of stopping the big guy from throwing boulder (because I dont have enough damage to burst the girl down if I didnt use Neji's mystery on her. Somemore my Guy can survive the boulder throw, so it doesnt matter). Use main's sealing jutsu on the big guy on bottom right. With main's sleeping standard atk, u could potentially make her asleep for whole fight (a bit of rng here)

Round 2: If the flute * top row is dead after first round, you should be quite fine. Use Guy's skill on the big guy on bottom right.

Round 3: Use neji's skill on the big guy in the middle. The rest should go quite fine since we are stopping the big guy from throwing boulder for most part of fight. Naruto and main's clone should be able to help to tank the big guy's standard atk. Use any skill that come off cd to take the enemy down.

Ninja exam lvl 82:

Fire main 16.6k power
Team: Guy, Naruto, Neji
Main Skill: 3 3 3 1 1, summon: Gamachu

x main x
x neji x
Naruto Guy x

Strategy:
Similar to 81-84, the key is to take care of the sound ninja girl.

Round 1:
Main's sealing jutsu on the big guy on top right. Neji's skill on the sound ninja girl in the middle row.(optional here, if ur damage is high enough to take her down with just neji,guy and naruto standard atk and combo, then neji's skill can be used on the other big guy to stop his boulder). Make sure your lowest hp ninja didnt die from the boulder throw (restart if it crits), and the sound ninja girl didnt crit and kill off ur team. Also it is best if ur main can successfuly make the top row sound ninja girl asleep throughout the fight (RNG)

Round 2:
Naruto's rasengan. The sound ninja * the middle row should be dead by now. The rest is just depending on RNG, where u pray that Neji and your main can withstand the big guy standard atk, and the sound ninja girl is asleep throughout.

Round 3:
Neji's skill on the big guy on the top right and Guy's skill on the big guy in the middle row.

Round 4:
Use rasengan to take down any low hp. Keep ur sealing jutsu for whichever ninja still alive to stop them from atking for one round. Auto.

*might need to try a lot of times and wish for the best RNG.