Oh god. Given how much trouble I had staying alive against the predictable 7F version, I think I'll wait with this one until I've finished the 10-12F maze.
Actually, the "whenever he feels like it" part is untrue. All the Foe enemies always follow the pattern of Flowing Hellfire -> 3x (Tackle or Slash) -> repeat. The problem comes if the AI roulette chooses to Tackle or Slash an empty spot due to someone dying, in which case it'll choose another move and target, but it still counts towards the pattern despite the move never going off at all.
In other words, if you can keep characters in the 4 main slots during every one of his turns, he'll (usually) follow the pattern. If you ever leave a slot open during his attack, you're leaving it up to chance whether it changes his pattern or not.
The fact that some of
moves does not have this "retargeting" is what makes the game crash on her sometimes if you leave open slots in your party. It's also why if you use
to sole tank and switching in damagers during safe periods method against her, sometimes she'll completely skip 1 or more of the 2 initial
that she always does with a full party out.
This might change during low health period though, that part I'm not sure of.