Each blade of The Waiting Storm is a shortsword +1. With every successful strike, a blade will generate one hit point’s worth of stored damage to a maximum of six points stored in each blade. These points may be expended as electrical damage during an attack; alternately, three points may be expended to hold a target for one hour if a save vs. paralysis is failed.
I really like paired magic items. I like to give them to different members of the party, though, and have them interact with each other. I’d just make a couple of tweaks to this item.
1) Instead of shortswords, I’d make them (or at least one of them) a two-handed weapon. I don’t want one ranger wielding both. Perhaps they are Mjollnir-like hammers? Or, if they’re shortswords, they hate each other: anyone holding both takes electricity damage.
2) Instead of damage potential “stored in each blade”, I’d have them both feed a single damage counter. Either player can expend the stored damage – which means that the other player can no longer do so.
3) To increase the game-theory jockeying, I’d maybe add another effect that is more obviously selfish than causing extra damage or paralyzing an opponent. Perhaps by expending 3 points, the user of one of the weapons can become become invincible for a round – or, more diabolically, expending 3 points does 3 points of damage to the other wielder, while giving, say, 6 points of healing to yourself. (The amount of healing can be tweaked: it should be just enough to make it an agonizing decision for the PCs. Maybe the hammers are evil and offer different amounts of healing based on circumstance.)
There, I’ve taken a perfectly nice magic item and turned it into a cursed source of interparty conflict. This is how I’d like to handle cursed items, by the way: not with -1 to hit, but with a mix of good and bad effects that the PCs can’t quite turn down. It’s like the One Ring: It causes invisibility, that’s pretty awesome. But it causes the end of the world, that’s bad.