What's important here is that Cybella (on her 5* form Gunsliger) can trigger the 2 archers and kai to attack. Formation is deoendent on cybellas aura direction
Sure Rhea is strong, but not that hard to deal with. A zerker can most of the tine, kill her in one skill, and with defenders obtaining the score tiles, (faye hd/altima pally = virtually unkillable) then you win. Unless you have two more squishies which most probably is the case, then you'd best pra...