Ended up being able to use this in-game, ended up going with a different mechanic for it though.

Kage Masamune [-1]
-Blood Drinker (Limitation: Only effective against creatures with supernatural blood)
-Cloak of Shadows
-Incite Effect (Manipulate Shadows)

Went with something a bit simpler, while still having a bit of the "draws power from a sealed monster" mechanical flair.

Holy crap I love that. Totally gonna use that.

Statted up an Item of Power as a part of some theorycrafting inspired by an old character and prepping for my first DFRPG campaign. I came up with this... then realized it was essentially a less good version of the Swords of the Cross. The concept behind this sword was loosely inspired by a section of the Zombie Survival Handbook that details the idea that there were groups of people often confused for Ninja who were responsible for keeping Japan free from Zombies. I took that idea and ran with it to the point of making them responsible for hunting down harmful supernatural creatures in general, not just zombies.

As an Item of Power it's a pretty solid piece of equipment, not overpowered while also not being completely unworth the cost. Creatively, it seems boring though. You guys have any ideas for something I can do to spice this Item of Power up a bit?

For reference, members of the Spider Clan referenced here would be statted up as Emissaries of Power. They have spider-themed powers; spider walk, inhuman speed, inhuman strength, Natural Weapon: Web (works like a weaker version of Breath Weapon, only gives an extra 1 shift of power rather than 2). Basically "Spider-Man: Demon Hunter".

Kumo Masamune
The ancient sword of the Spider Clan, wielded by their greatest swordsman for over nearly eight hundred years.

Yawarakai-Te
Forged by the greatest swordsmith ever, Kumo is a sword of utmost purity. It cuts only when needed, and saves all its cutting power for those moments so that it may cut true. This sword was forged and enchanted as to be able to destroy any monster it came against, and as such the wielder can spend one Fate Point to satisfy whatever a creature has a weakness to with the sword.

Hantā no burēdo
The Kumo was forged to slay dangerous beasts and keep the common people safe. If swung with the intention to slay a mortal of any kind, it will pass through the target harmlessly. The sword henceforth cannot be weilded by its master until the wielder has redeemed himself or it finds a new master.

Masutā no tamashī
Kumo has passed from the hand of one master swordsman to another for centuries, and their physical prowess has been imprinted upon it. When facing supernatural enemies, the wielder gains a +1 to attacks made with the sword.

Has anyone taken a crack at converting existing Supernatural Powers and Mortal Stunts from DFRPG to FAE? I like FAE a little better than Fate Core, but I don't wanna have to wait a full year to use it for Dresden if somebody has already done some conversion work.

Taking advice from this thread into consideration, I've updated the holy ninja to the following. It assumes Submerged level play.

Bless This House (-1)
Guide My Hand   (-1)
Holy Touch        (-1)
Righteousness    (-2)
Fidelacchius       (-3)

Human Form+Rare Change (+2)- Shin can only change into Shade Form when he has stolen the shadow of a living (or formerly living) being. Shin will only take the shadow of one whom he has been forced to kill in combat.
Shade Form includes the following Supernatural Powers.
-Cloak of Shadows (-1)
-Shadow Manipulation (-1)
-Superhuman acrobatics (-1)

Gives him a final refresh of -9.

It doesn't change your equipment the way your typical Magical Girl anime transformation does, at least not explicitly. That's pretty much it, though.

So, reading this thread and some recent announcements in the nerd community got me thinking about a power. My first time designing anything in this system, so I'm sure it's gonna need some balancing.

Magical Soldier (+2)
You are completely indistinguishable from a normal mortal most of the time. However when the chips are down you have an ace up your sleeve, a seemingly mundane object which triggers the awakening of potential inside of you. Your attire changes to that of your Soldier Form, and powers that were otherwise inaccessible to you become unlocked.

Soldier Trigger- You have a small, otherwise mundane item in your possession. Holding that item and speaking an incantation activates your Soldier Form. The incantation and transformation takes your entire turn. Your Soldier Form looks identical to your normal form, except for minor differences in things like hair length and eye color, and your attire changes.
Block- You have a mental block which keeps you from accessing your Soldier Form without your the item in your Soldier Trigger. The Soldier Form is not granted by the item, you just need it to access the Form.
Soldier Power- Any Supernatural Powers you have (At least 3 Fate Points' worth) which do not come from an external force (Faith Powers, Sponsored Magic, etc) must be tied to your Soldier Form, and cannot be accessed or used when in your normal form.
Soldier Gear- Any armor, weapons, or magical gear you own is tied to your Soldier Form. In your normal form, you can't carry anything more dangerous than a pocket knife.

Edit: The news was that they're remaking Sailor Moon.

Sounds like a solid plan.

If you're interested in custom Powers, there are a bunch that might fit.

Superhuman Acrobatics comes to mind.

And I've got rewrites of Feeding Dependency, Holy Touch, and Bless This House.

Where would I find those? Those sound really cool.

Edit: Oh man Rune Magic would be perfect if I were trying to play just a straight ninja-style character.