 This ritual is only performed during times of great peril.Normally the clan deal with whatever threats presented itself to them but sometimes the clan itself was in peril or they faced extinction; in times like this Apocalypse was summoned.The consequence for asking for Apocalypse's help, however, was that one of the Inner council would be killed; since asking for Apocalypse's help meant they were weak, the fittest should never have to ask for help.