Darkest night
Shortly after the end of the Autumn Equinox, the stars start going out all over the Empire. The Empty Skies phenomenon spreads to cover not only the remaining Imperial territories, but also the formerly Imperial territories of Liathaven and the Mourn. During the day all is well, but at night the skies are empty of stars; only the moon is visible. Only the skies within a mile of Anvil appear to be exempt - there the sky appears perfectly normal. Needless to say this is causing quite a bit of excitement among Imperial astronomancers.
There appear to be two game effects. The first, which is unlikely to be relevant until the start of the next event, is that every territory is under the effect of a very powerful shroud, most likely woven with Night magic, that interferes with the casting of scrying a divination rituals such as Eyes of the Sun and Moon, The Eye of the High Places, and Dreams in the Witch House.
More importantly, every naga in the Empire experiences the following roleplaying effect; their natural urge toward subtlety and secretiveness is greatly strengthened. Naga in general relish being mysterious and secretive, but while experiencing this potent roleplaying effect they may need to make a significant effort of will to answer direct questions or be honest about their intentions.
The effect applies to all the territories of the Empire, to Liathaven, and to the Mournwold. This is effectively the same effect as detailed here, but it now covers everywhere players are likely to be possibly while they are there.