So, I've been thinking about a Martial Art centered around hammers in the way that Single Point is centered around slashing swords.
What I've realized is that it would be, in a strong but not total sense, "Solar Hero Style, but with a weapon".
Heaven Thunder Hammer or some variation is a Must for this style, as are cousins of Sledgehammer Fist and Shockwave Technique (the "knock a muthertrucker into another muthertrucker" Charm).
Of course there are no grappling Charms, but instead it draws a few concepts from Earth Dragon Style. The 3rd Edition versions of Force of the Mountain and Shattering Strike, definitely. Weapon-Breaking Defense Technique would be great for a clashing Charm, especially since this Style would be really weak on defense. Earthshaker Attack is a given, though it won't have the finesse that 3rd Edition's version gains (with its follow-up decisive attack against one target), since the hammer-style doesn't manipulate the element of Earth.
Right now, the metaphorical concept is hovering between "lightning bolt" or "meteorite", with a definite concept of "the heavens are throwing something to the earth that shatters a fucking mountain in one blow".
It's "Thor and Mjollnir, the Style". It's Nora Valkyrie before factoring in her weapon's "Rocket-Propelled Grenade" launcher half.
Speed and grace are not this style's strong point. It's all about hideous damage, unstoppable collateral destruction, "the best defense is a brutal offense", and a great big final "fuck you and everything around you".
There WILL be a Charm to throw the hammer. This is absolutely vital to the Style's image, but also obviously not conducive to continuing to use the Style, since it can't be used without a hammer. The balance point is making it very obviously the LAST move; the attack you hold in reserve to finish the fight. Thus, throwing your hammer may be the capstone. Using it when you have the form Charm active will cancel the form, but in return it will enhance the throw.
I envision a spinning flurry attack that potentially hits EVERYONE in close range of the martial artist, including his allies. Taking a cue from how Steel Devil Style has Charms "chain" into other Charms, the spinning attack will allow the martial artist to use the throwing Charm as a second attack within one turn, and the throw will gain strength based on how many previous, consecutive turns the martial artist was spinning the hammer. (With a cap, of course.)
The earthshaking attack will also affect allies as well as enemies. To quote Starcraft's Siege Tank, "Time to drop the hammer, and dispense some indiscriminate justice". This style is unrestrained and wildly destructive. You will be a threat to everyone you can reach.
The earthshaking attack will ALSO be compatible with the throwing Charm, so that you can "shatter the mountain down on earth" from a distance, just like the wrathful god the style emulates.
At present, I'm allowing one-handed hammers, but this style will either reward two-handed hammers or penalize one-handers, or outright drop one-handed hammers.
Mjollnir was one-handed by accident; its haft was meant to be longer, but Loki fucked it up. It would also be nice to allow users to use the style with a one-handed hammer in one hand and a shield in the other; they've have to use Melee Charms or a Shield-oriented Style to kung fu with the shield, but at least this hammer-style wouldn't outright shut that down.