A day that only occurs once every hundred years. This day comes with a sun eclipse and nine planets that align together and increase evil's powers while weakening the good. To muggles, it doesn't mean anything other than an ordinary sun eclipse, but to power-users, it is a bad omen as the power of the good weakens and demons can walk around the Earth days before the eclipse even arrives. This day won't last for long, but while it does, evils can take advantage of it to become the ruler of that dimension if the ritual is performed right.