What, the enemy girls in the timed event stages or the special mercenaries stage? The former should be Velvet and Christia from platinum recruit (at least in the 20 AP stage, don't remember which girls are in the other stages). The latter should be *spoiler spoiler spoiler*


Regarding the special mercenaries stage, the big hint is: do you notice Mono's presence? What do you remember about Mono's lore/background?



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And one more spoiler tag for those who want the direct answer on who the girls in the special mercenaries stage are:


Aside from Rosa, they're definitely members of Eleftheria, as seen in Mono's event. Rosa's presence here suggests that she's joined that group. Interesting that Kai isn't here though; she's the last confirmed member.
What else has Eleftheria done? They were also the mercenary group mentioned to be at top of the rankings in the Xmas event's scenes.