Even though we only have one round of synergies unlocked, I went ahead and mastered the first and second Nemesis weapon fights. First one wasn't too bad, but the second was a big bump in challenge, especially with only II, VIII, and X synegies unlocked. Team I used:
[xtable=skin4|600x150]
{tbody}
{tr}
{td}
Unit{/td}
{td}
Skill1{/td}
{td}
Skill2{/td}
{td}
Soulbreak{/td}
{td}
Record Materia{/td}
{/tr}
{tr}
{td}Terra{/td}
{td}Power Breakdown{/td}
{td}Mental Breakdown{/td}
{td}OSB{/td}
{td}+13% Mag & Res{/td}
{/tr}
{tr}
{td}Onion Knight{/td}
{td}Wrath{/td}
{td}Entrust{/td}
{td}---{/td}
{td}Ace Striker{/td}
{/tr}
{tr}
{td}Aeris{/td}
{td}Curaja{/td}
{td}Protectga{/td}
{td}BSB{/td}
{td}Lionheart{/td}
{/tr}
{tr}
{td}Tyro{/td}
{td}Magic Breakdown Dance{/td}
{td}Multibreak{/td}
{td}Wall{/td}
{td}Mako Might{/td}
{/tr}
{tr}
{td}Yshtola{/td}
{td}Curaise{/td}
{td}Shellga{/td}
{td}BSB{/td}
{td}Dr. Mog Teaching{/td}
{/tr}
{/tbody}
[/xtable]
Roaming Warrior: Onion BSB
Terra's OSB did 99.9% of the damage this encounter, since I wanted to use the absolute minimum amount of attacks possible so I never had to eat an Ultima (which triggers after your 10th attack). It took 6 OSB's to finish him off.
Onion Knight did nothing but wrath up and entrust his gauge to Terra. Terra called in the OK BSB roaming warrior for group buff and to put herself into burst mode (+20% stats), then she helped with breakdowns and OSB nuking. Tyro did wall and breakdown dances (dances don't trigger the counters). Aeris and Yshtola just did nonstop healing. I won, but it was close since my Terra was slowed most of the encounter (I only have 4 slow resist accessories, so they went to support / survival units).
I need to wait until all of the synergies unlock before trying the epeen only final version, but I have serious doubts I can beat it without native OK BSB, since I'll have to use RW for last stand instead. Maybe, we'll see, but I'm not going to lose sleep if I can't beat the final version since it has no rewards aside from bragging (though I would like to say I beat it... lol).
Video:
Nemesis (Descent D180 difficulty)