While, on the other hand, players who run water main with poison tai or that run skewering with experimental ninjutsu are quite hard to beat given the average lineup you find there, overall if they use monkey king as summon mystery.

@op:

In zenith you win on the bad ninjas side more than on the good ninjas side, so who you choose among the ninjas that cost 0/1/2 is the key factor.

The idea is to get 3 decent ninjas (dodge whatever costs 6 or higher points unless is hokage minato that in arena is too op) and 6 bad ninjas so that you win on the 2nd-4th matches and you have a good chance to own initiative 3 times.

Generally the best mains for this feature are wind (clones, flower guard and dance of impetus/sand dust op) and water (skewering every round + sure chaos and op clone with monkey king summon mystery op if you face wind or lightning main and poison op if you face earth and fire main and the best versatility with bad ninjas the game has yo offer) with fire main as the 3rd best option. Lightning and earth main are too dependant on the other 3 ninjas to be an option for this specific modality.