Avatar Crisis; Second of the Seven

Weapon: Wand
Material: Golemhide
Runes: Truefire, Aquifer, Miasma, Silver cord
Smith: Signum

when they were asked to be a magical girl they knew what sort of soulweapon they wanted, they wanted to be like Aang the avatar wielder of the four elements wind (Squall) water (Aquifer) earth (Terramancy) fire (Truefire)

sure, signum couldn't forge a weapon with both Aquifer and Terramancy but they could just use Siver Cord to link together Golemhide's sheddings, while the shedding would lose access to the soulbond after detaching they could circumvent that from happening by connecting it with Silver Cord first, thus letting the sheddings benefit from all of their runes including Silver Cord itself even after detaching, they could even make armor with it

however there is a problem, them and five others are left to be chosen, 6 runes of Wither are left to be chosen, and there is no leeway in remaining runes, they must take a Wither rune, so the question becomes which rune to replace, Miasma for Squall? it is still kind of air related after all, Bloodlet for Aquifer? it would be stronger if they could get blood to use, or suture for Silver Cord

Bloodlet is the first to be eliminated, there are 5 Prana runes left, so if they didn't take one of them then every other magical girl would be required to take a Wither and a Prana rune, they would not inflict such an injustice upon them if reasonably possible

Suture would be an interesting addition, instead of manipulating the Golemhide sheddings with Silver Cord they could instead make limbs from suture to lob them at high speed almost like those ancient slingshots, but other considerations are more important

Miasma wins, mostly because they need to be able to see through the miasma to properly blast the entire area with their other runes, to make sure they can avoid friendly fire while doing so, if another magical girl had Miasma then they might find themself in a situation where they cannot attack because of fear of hitting an ally, not having Miasma could render them impotent thus they must take Miasma

as for their alias, Avatar Crisis, they chose it because it is a reference, not just to Aang, but because they are going to bring a time of troubles on all of their enemies :P