O Night, and by the spirits that preside over theeIn all conventional mythologies Night is a figure of discord and threat. As she appears in Book I of Spenser's Faerie Queene, she is represented as "griesly Night, with visage deadly sad" (I.5.172), testifying that "I the mother bee/ Of falshood" (I.5.240-41). The eldest of divinities, she has unimpeded access to the depths of Hell. In Paradise Lost Night dwells with Chaos in the "dark/ Illimitable ocean without bound" (II.891-92) from which God creates Hell. Whatever Victor thinks he is doing by solemnly invoking Night to aid him in his revenge, it is clear, by all traditional associations, that no good will come of it.
The observant reader may recall that the Creature invoked figures associated with the daytime in swearing before Victor that, if he were given a partner, he would never trouble his maker again (see II:9:17).