This might be off topic, but you know, the Swords of the Cross make me wonder if there isn't an equivalent for the Other Side. Swords of the...Bad Things. Like cursed Swords that are powered by suffering.
I know, I know, they're supposed to oppose the Denarians, but I'm talking about inanimate, powered objects designed to be used as weapons, not receptacles for Evil Things.
There are some things, but AFAIK not (that we've seen so far) things of the Fallen. I don't think the Fallen
get to make "anti-Swords"... The Swords balance the Denarii, and if the Fallen try to make anti-Swords in opposition to the Swords, they'll either find one of the Archangels there, going "yeahNO;" or they'll find some OTHER new creation of YHWH opposing their anti-Swords (and generally
Doing Good In The World alongside their mission, just as the Swords and the Knights already do).
But as to "evil" items...
The Blackstaff, which Harry intuits is semi-sentient and revels in death & destruction.
The athame which channeled Nemesis was, apparently, rather a dark item even before that.
Several of the ritual items -- as examined by Bob from the photo's -- that appeared in
Changes.
The Stone Table, which is about taking Power -- especially death/lifeblood -- and/or binding power.
Even things like the Hexenwulf belts... overtly, they're about the shapechange and the resulting personal power; but their real potency is in subverting the will of the wearer. They are weapons used against the minds of their wielders.