I got this legendary today (sadly , the only reason i set the loot for sub ist to get the boots someday) and I wondered, if it is worth to use FoK on a single target instead of a mut. It will only give 1cp / 2 with a crit, but the energy cost is lower. For fights like Nythendra or Ursoc where you can time it in order to deal good dmg it is actually prette decent.