5/8 on Ragnarok. Mordred method was reliable and most of the time I didn't have to deal with a Rage overdrive. Rather, the move that absolutely had to be countered was the normal overdrive since the single-target damage is so high. Gaia reliably counters that, but filling your frontline with Cybele and Brynhildr would've also worked, though somewhat less reliably. There's a lot of things that can go wrong in this fight, as the boss can deplete the Burst gauge and most people won't be able to endure a full rage phase without using Burst. This can occur because of timing issues with the Overdrive meter or simply because the Burst meter hasn't been filled when Rage commences, potentially punishing those with higher DPS. Both can be somewhat mitigated with skills that affect the Overdrive meter, such as Raphael's, and the latter can be managed with dizzy (which has the side-effect of making timing issues more likely).