Borreal Knight
I'm down with that. I have a few questions on your idea, though.
-What is the maximum amount of markers that can be placed on a card?
-How long would a marker last and what are its conditions for removal, if any?
Dancer
I wasn't too sure with Impale myself. I was going for something mechanically akin to Grimnak's Chomp, but that fact that Impale is "instead of attacking" leaves it in a weird place and at odds with the rest of her kit. You voiced my concern well. Here's something that works a lot better, and that I think reflects her in-game grab attack more accurately:
Grasp
After moving and before attacking, choose one small or medium figure adjacent to Dancer of the Borreal Valley. Roll the 20-sided die. If you roll an X or higher, the chosen figure cannot roll any defense dice if attacked with a normal attack by the Dancer this turn. This power cannot be used if there are 4 or more wound markers on this card.
The way it works in DSK is that if she grabs you, while you are helpless in her grasp, she will then impale you with her blade. It's infamous for killing most players outright. With an above average attack roll following a successful d20, this should kill most small to medium heroes. The closest comparison in terms of power is Chomp (which is on a more fragile 120 point figure), but Grasp is less reliable since the damage is determined by the follow up attack instead of it being an assured kill, and it squad figures have the same check difficulty as heroes. However, Frenzy will occasionally give her a another chance per activation.
This is what she would look like:
If it works out well with her, then we might be able to use this power as a template for other enemies who have a similar grab attack.
Titanite Demon
I'm glad we're on the same page. While thinking about the relationship between a character's locomotion and how it's abstracted on the game board, I realized that some of my assumptions might have been incorrect. For example, after recalling the Anor Londo Sentinels' slow and heavy movement, my first instinct was to give them a move of 4 like the Knights of Weston, as they were the most similar unit to come to mind. But then I remembered how SLOW they ACTUALLY were. Lumbering slow. They might even be slower than the Titanite Demon in-game, for which my first instinct was a move of 2 or 3. Without discussing what we should do with the Sentinels, perhaps a move of 3 would actually make sense for the Titanite Demon. Let's take a look at the classic units. The Granite Guardians have 3 move (the lowest consistent move value in classic 'scape), but they try to compensate for it by having the ability to climb height as if they had a move of 5 (a-la Sgt. Drake Grappling Hook). I have been sticking with 2 for the Titanite Demon because I thought it would be closer to the source material, but if we find 3 to be more faithful or just better in every sense, then I have no problem balancing him around that.
That brings another thing to mind. Something to consider when balancing a unit around a specific stat is how the unit's power will change when that core stat is changed. If you have control of the Glyph of Velda and TD starts hopping around with 4 or 5 move, what will the implications of this be? Is this something we should be concerned with, or is it a natural and healthy quirk of the game system that promotes variety and creates interesting and fun situations? Will being able to draft him with a custom unit that increases his movement break him? The more extreme we make his move value, the more drastic the change to his power will be when it gets boosted. Just something to think about.