I saved enough level up points to be able to buy two levels of smite and that gave me enough of a fighting chance to eventually beat her. This enemy is in need of some serious rebalancing, though. All the tentacle attacks cause ridiculously high weapon grip degeneration, so if you use any type of attack that has partial parry while she's attacking you'll be disarmed. Since her attacks have no stamina cost or stability cost, she can spam them without consequence and you're at her mercy until she decides to guard for a turn and give you a chance to go on offense.
Her attacks really need to have high stamina costs or mana cost or -something- to offset how much shield damage and weapon grip degeneration they cause; right now you have to create your own openings with lightning and your survival there is total RNG since it's a two-turn cast process. Couple this with the fact that you don't ever seem to start with a full mana pool in story mode and have to chant for a couple of turns to charge up first and this fight is just an absurd roadblock.
Tentacle witch is hardest enemy in the game IMO.
She gets a bonus to disarm based on how much faster than she is than you, and if you're being predictable
In story you don't have to fight her - just surrender and tell her to piss off. She listens.
Easiest strategy in my experience for story mode is sleep + oil + paralyze + inferno
Then the details of each enemy aren't even that important
Using "Fade away" on the last turn of a battle means you'll get 50% evade on the first turn of the next battle (weird I know)
BTW there's a bug where "incanter" doesn't work - item master does what incanter is supposed to do in addition to its intended purpose
