So how much damage can this baby deal when used by someone with inhuman or supernatural strength?. Also I'm currently trying to figure out an application of Tengu magic by using enhanced air pressure to increase the impact power of an melee or projectile weapon like an arrow or knife.

 I like the idea of an Iaijutsu based power,though I'm wondering if it should be edited so it's worded better or just rewritten entirely.

Here's an rewritten version of Sword of the Great Tengu,hopefully that makes more sense
Sword Of The Great Tengu [-3]
Description: This an exquisitely made katana traditionally used by the Tengu Clan’s current prince or chosen emissary as a symbol of their authority and grants the wielder access to a small measure of the king’s sword skills while in combat.
Musts: You must have an aspect related to your possession of this item.
Skills Affected: Weapons
Effects:
[-0] Purpose. The Sword of the Great Tengu was crafted by the Tengu for the use of a skilled warrior in an effort to stave off the decline of swordsmanship in the world. This Item of Power may only be used in defense of one’s self, one’s comrades or one’s lord .If the user ever leaves the path of the sword behind as defined by the Tengu this item will not work for them in a mundane or a magical sense
[-0] It Is What It Is. An extremely well made Katana. It is treated as Weapon: 2 when used in one hand and Weapon: 3 when used with two hands.
[-0] Unbreakable. As an Item of Power, this item cannot be broken except with a magical ritual predicated upon perverting its purpose.
[+2] One-Time Discount. The Sword of the Great Tengu is not easy to conceal, because it's a sheathed Katana
[-3]  Tengu’s Guiding Hand: The sword is possessed by the Tengu King via a mind meld, who guides their sword at need. The user gains the full effect of these abilities provided they are physically holding the blade:

True Aim: When swung in keeping with its purposes, Sword of the Great Tengu grants a +1 to the wielder’s Weapons skill.

Always at hand : The sword appears, drawn and in its wielder's hand, as combat is initiated.  If the wielder is surprised, the sword will defend at Good automatically.  If the wielder is initiating combat, this forces an Avoiding Surprise roll even if the victim was aware of the wielder.  (Note:  This only works once against any given target.)

Unnatural Edge: The sword treats Toughness powers as if they were one step weaker (Mythic becomes Supernatural, etc.),and deals a +1 bonus to hit and inflicts two additional stress.

I'll price it whatever you guys think is appropriate

I actually remember the gruffs wearing gloves when they attacked Harry including the trench coats,

Probably something to do with bladed weapons.

Ok thanks for the feedback guys,I'm working on the changes now. I was hoping someone could help do a write up for Tengu magic similar to this http://www.jimbutcheronline.com/bb/index.php/topic,25794.msg1291357/topicseen.html#msg1291357. I know that Tengu are know for their specialization in air magic and  shape shifting and possession but considering they're considered the founders of ninjutsu as well,maybe include some of the more mythical ninja abilities as well?. I know a certain breed of water  Tengu related to the kappa is able to launch  "strange" fireballs so maybe it depends on the type you learn it from?. I'd include it as normal ability just to be fair.

I mainly want to see a build of Susan during Changes as Martin  can stay the same with a few alterations. She probably has a much higher discipline,gets enchanted items from Lea, temporarily wields a Sword of the Cross, can swing an mean club and has enough speed and stealth to get the drop on the Ick in addition to having info about the Red Court's high ranked key players.