Looks like it's been a while since anything new has been posted here, so I thought I'd put something from my own game here for other folks to use.

Yata no Kagami - The Mirror of Amaterasu [-4]
History: Yata no Kagami is a sacred mirror that is part of the Imperial Regalia of Japan. It is said to be housed in Ise Grand Shrine in Mie Prefecture, Japan, although a lack of public access makes this difficult to verify. The Yata no Kagami represents "wisdom" or "honesty," depending on the source. Its name literally means "The Eight Hand Mirror," a reference to its octagonal shape. Mirrors in ancient Japan represented truth because they merely reflected what was shown, and were a source of much mystique and reverence (being uncommon items). Japanese folklore is rich in stories of life before mirrors were commonplace.
   In the Japanese mythology this mirror and the Yasakani no Magatama were hung from a tree to lure out Amaterasu from a cave. They were given to Amaterasu's grandson, Ninigi-no-Mikoto, when he went to pacify Japan along with the sword Kusanagi. From there, the treasures passed into the hands of the Imperial House of Japan.
   In the year 1040 (Chokyu 1, 9th month), the Sacred Mirror was burned in a fire. Whether that mirror was irrevocably lost or not, the current government claims that there are three sacred relics, each held at a different Shinto shrine: one is in Meiji Shrine in Tokyo, one in Ise Grand Shrine, and one in Atsuta Shrine in Nagoya.
Musts: An aspect justifying your possession of this item.
Skills Affected: Conviction, Empathy, Lore
[-0] Purpose: To illuminate and purify things - darkness, lies, inner natures, dark desires, etc.
[-0] What it is: It's a mirror.
[-0] Unbreakable: Okay, it's an unbreakable, mythically empowered mirror.
[+2] Item of Power discount: It's not big (about 8" in diameter), but you can't hide it in your shoe, especially when you're using it.
[-1] Amaterasu's Gift: With a brief thanks to the Sun Goddess and a symbol of your faith in her, you can roll Conviction to place the aspect "bathed in Divine Sunlight" on the zone you're currently in.
[-1] Insight: +2 Shifts when using Empathy to determine another sentient being's High Concept or Trouble.
[-2] Purification: Roll Conviction to inflict a Weapon 2 attack on your current zone, capable of damaging ONLY targets that have the Catch "Divine Sunlight" (or similar) on their Toughness powers.
[-3] True Sight (Supernatural Senses): Use Lore to detect lies, hidden things, the presence of beings masked by veils, glamour, shapeshift or flesh masks.

At the more lenient end of the spectrum, it's not unreasonable to state that Renfields are "brain dead", given that you have to Take Out the target with Domination (or a similar custom ability) to create one. In this case, "dead" is replaced with "brain dead" as the result of being Taken Out.

You could presumably extend this logic to include people who were permanently transformed in to something else. Doing this is prone to permanently shattering their minds, effectively "killing" them.

Re: a human mind not being able to handle True Shapeshifting... well, this character isn't entirely human, to begin with, so I'd half buy into the idea. The other half, the part that IS human, isn't going to be so lucky. Remember, the character ultimately has to face The Choice, and in my head, every time he changes into something radically NOT human, he's drifting away from choosing "human". He should have an easily-compelled Aspect to cover this; perhaps Takes A Monster To Know One (maybe replace the ASPECT: Family Of Monster Hunters).

Downgrade the Physical Immunity to Mythic (still usually seen in NPCs) or Supernatural Toughness (more acceptable at PC level). Sure, he's the scion of a spirit being... but until he Chooses "Fetch", he's stuck with a body made of normal matter, regardless of what he's shaped like at any given time. Also, the standard fetch Immunity is 'only against magic, and only when the caster is afraid of the fetch' (OW44). Generic, full-spectrum Immunity isn't a typical Fetch trick.

Much of the above brings up my biggest issue with the character, from a GM and story standpoint: nothing about the character, other than his Trouble, says "Fetch". I'd more expect something like Emotional Vampire: Fear somewhere in the mix.

As far as his 'unpowered form' is concerned, I'd be more likely to accept the discount if there ARE ways to to get him into that form. Otherwise, I'd go with Human Guise (-0) (YW176), which allows him to look entirely human UNLESS he makes use of his supernatural abilities. I tend to fall back on the mantra "If it's not a disadvantage, then you don't get a break for it being a disadvantage" for situations like this.

Trouble: Damn the kharmic reincarnation lottery!

Still love it, too. Just have no one here who runs it, at the moment.

Dude, is your player Dean Koontz? 

No, but I'd recently read Koontz's Frankenstein pentalogy, and had been tinkering with adding some of it to the upcoming game. When the player in question described what he was wanting to play... yeah, you can figure it out, from there.   

Another one:  The US government employs warlocks, specifically psychomancers, to cover up any supernatural crises that become too public.  One minute a bunch of guys in black suits walk in, the next you have no idea what happened to the last day of your life but strangely, it doesn't bother you...

And now I hear this in my head:

Jay: Did you ever flashy-thing me?
Kay: No.
Jay: I ain't playing with you, K. Did you ever flashy-thing me?
Kay: No.

Sounds like I've succeeded in my intent, then. Apologies for the terminology confusion; in my own head, such things are pretty malleable, as long as I know what my intent was. I've played a lot of other "reason from effect" games before, such as Champions (Hero system), so the tendency is a bit inevitable, I guess. 

Heh, if you want a purely homegrown one that I'll be using in my own game, feel free to use Forethought Technologies, Inc.

I leave you to tweak this however you will for your own game, but here's the nutshell version for my own game. Forethought is the meaning of the name Prometheus. Rather than the Greek titan, it refers to Mary Shelley's book, Frankenstein, or The Modern Prometheus. Forethought Technologies, Inc. is owned entirely by the insane biomancer, Victor Von Frankenstein, under another name.

Why is this even in my game? Because one of my players wanted to play a "magical construct that became self-aware". He's Frankenstein's original creation, now known by the name "Deucalion"... the mythical son of Prometheus.