Vobist

Vobist the Faint is one of the Star Signs of the Old World. It is the Sign of Darkness and Uncertainty, having no stars, and instead appearing as an empty spot in the heavens. It is in Ascendance during Autumn. People born under it are known to be ambiguous, erratic, and uncertain.

Overview
When Vobist is high in the sky, the Witch Hunters are on the prowl. Mental illnesses (often mistaken for witchery) are at a peak during this time. This has a similar effect as when Morrslieb waxes full. Characters born under this sign are uncertain about the world around them. They tend to act erratically, almost schizophrenically, at times.

Source
Warhammer Fantasy RPG 2nd ED -- WFRP Companion pg. 51