Nybbas isn't used to the idea of actually protecting cultural concepts, rather than just sucking out their juice and tossing them to one side, but there's a first time for everything.

The various Chinese ethereals got co-opted into the August Prosperity Collective during the Bad Times, a fact that pleased neither them nor the kami. Human history since has done nothing to improve the relationship. In fact, there's some indication that certain of the more wicked oni meddled in Japanese politics during the earlier part of the last century, for the express purpose of encouraging an invasion of China.

That conflict (which sort of turned into World War II, eventually) was probably inevitable, but the native Chinese spirits were certainly not amused. Their retaliation involved the isolation and destruction of several of the kami's carefully assembled collection of Emperor-dreamshades. So the kami answered in their turn with encouraging the breakaway island republic of Taipei, which led to the sabotage of one of the kami's few remaining Ethereal Tethers, which led to...

Look, suffice it to say that there's bad blood, OK?

Now, from the outside none of this ever used to show (both groups were careful to maintain a united front in public), but the situation's really starting to destabilize. Neither side seems to care much anymore if their Infernal overlords are watching, the more ethical spirits on both sides are getting sicker and sicker at the internal politics going on, and there's always those damned non-aligned Genius Locis from the outside, stirring the damned pot. There's already been a defection or two: better life on the outside than in the snakepit that the Imperial Court(s) have become.

The Prince of the Media has decided to quiet things down. It's starting to make him and Beleth look bad, and that simply isn't permissible. The PCs get to play peacekeeper for a while (it helps if they've got ethereal experience, of course, but what's really important is that they can seriously shred things). Their mission, which they have no choice but to accept, is to keep the lid on, however they like. Just don't kill anyone who's under contract... that, of course, means everyone involved, including the other PCs.

Now, watching a bunch of demons try to bully, smash and bat ethereals around without actually killing one (and the bluffs will get harder and harder to make) would be funny enough, but there's a wrinkle (of course). It would seem that a certain oni has decided to handle his favorite enemy by going to the source. He's somehow got his hands on a bunch of people who like making poison gas and don't like Chinese, and he's planning to connect the two at the traditional Chinese holiday of the Lantern Festival. This will have bad consequences, and may even decrease Nybbas' market share as his contract workers go on 'sick leave' (read: "all out vendetta"), so that simply can't be allowed to happen.

With any luck, all of this should be deeply ironic to the PCs as they try to defuse the triggering mechanism. If it isn't, toss in the squad of Ofanim of the Sword who happened to be in the neighborhood. They probably won't believe that the PCs are actually trying to prevent a juicy Media event.

Well, let's be fair. It is a little unlikely.