Interesting stuff.

The whole "people come here to die" theme feels fertile, supernaturally speaking. Pretty easy to tie a variety of different magical threats into that.

I'd be inclined to offer a 50% refund on evocation and no refund on thaumaturgy.

Unfortunately, I suspect that such a limitation would encourage undesirable patterns of play among evokers. Would never be worth casting a maneuver with it, and you'd be strongly encouraged to go for a one-hit-kill in every fight.

Next question: What powers do you think a praying mantis-type theriothrope should have?

Probably nothing interesting. Thropes don't seem to have much going on.

What level of limitation would you apply to one that does not actually STOP someone from using a power, just radically incentivizes against using it? I'm thinking of a scenario in which someone has powers whose uses end up being too costly for them to use often, which I would mechanically represent by automatically creating an aspect for the GM to tag against the person for free later every time they draw on the power for an exchange.

Depends on the Power, honestly. It's a pretty crippling drawback in a direct conflict, but not too big a deal outside of one.

Yes, compels will work. But compels will also work for preventing a loop garou from changing when its not the full moon and being forced to change when it is, and yet they still get a rebate from human form--rare/involuntary change. How is what I'm doing different?

As I said, rebate Powers modify normal Powers. Your Oathbreaker Power does other stuff, like hitting you with mental stress.

That said, there's a bias on this board towards using Compels over rebate Powers. There's a good reason for that bias; Compels play better. Even in the case of the loup-garou, it's healthy to use a fair number of Compels.

Compels are at their best, and rebate Powers are at their worst, when it's unpredictable how often your weakness is going to matter. So "you're weaker when you're facing the person you broke your oath to" is a classic Compel thing.

Edit to avoid triple-posting: How many shifts of power would be needed for a Darkhallow? And do you think one could be cast at Chichen Itza, now that all the vampires are dead?

I don't think Chichen Itza could sustain one. My understanding is that you need to eat a whole bunch of souls to make the thing work, so there needs to be a large + dense population present.

As for the shifts, it's really up to you. The game has never made anything about the Darkhallow clear, as far as I can remember.

In general, rebate Powers are only used to modify other Powers. You can't really get Refresh from a weakness in this game, you can only reduce the Refresh costs of your strengths by limiting their usefulness in some way.

Compels pick up the slack. On its own, The Catch just makes you as vulnerable as a normal person to whatever your Catch is. If you're more vulnerable than that, you get Fate Points.

Anyway, here's Limitation.

I'm trying to come up with 12 demonic lords, and right now I can only think of 3: the demonic lord of emptiness, the demonic lord of deception, and the demonic lord of pain. Can you think of any others?

I figure you can probably use any vaguely negative-sounding concept. Fear, gluttony, bigotry, foolishness, bureaucracy, pride, vengeance, sorrow, laziness, whatever.

I have no idea what the canon answer is, but if I was running the game I'd say that the flounder can grant any imaginable wish partway. No matter what you wish for, you can get a slipshod and incomplete version of it.

Dunno why, but that kind of thing just feels flounder-y to me.

The effects of the individual marks sound like they'd be best represented through Aspects.

For the effect of all the marks together, perhaps you could use Variable Abilities with a Limitation.

...well, damn. Looks like the wiki's been overrun with spambots. And here I was thinking being preposterously obscure would protect us.

Well, it should be possible to revert to an earlier version. Gonna be a pain in the neck, though.