The Fallen One
The Fallen One was a multi-dimensional entity.
It was “the gestalt consciousness of thousands of the many monsters felled by the Shifter — held together by hatred and vengeance and the all-consuming power of Chaos”. After coalescing in a universe that was ruled by Chaos, the Fallen One lay in wait until a day when it perceived that Jenny Everywhere had disappeared from the Multiverse of her own accord.
It emerged in the form of an oppressive, shapeshifting fog in another universe, in a seaside town where Jenny's friends had congregated to mourn her, intent on destroying Jenny's “defenceless” loved ones in her absence as a way of finally getting its revenge. However, Jenny's companions proved capable of driving back the dark entity almost completely, and it was finally completely dispersed when Jenny returned, literally dropping out of the sky and onto the ‘head’ of the Fallen One. (PROSE: The Disappearance of Jenny Everywhere)
After the collapse of the Multiverse into the “Collapsed Cosmos”, the “All-Devouring Chaos” and the Fallen One were smushed into one, much less powerful being going by the name of “Typhaon”. He had the physical form of “a glowing, seething green orb”. Finding a despondent Jenny Everywhere sitting on a park bench, the entity proposed to fight her, beginning to gloat about how he had found her at her weakest, but Jenny refused to interact with him, claiming that it “just [wasn't] the same”. Admitting that she was right, Typhaon left, promising to get his revenge on her later when the Multiverse was restored. (PROSE: The Hermetic Garbage of Jenny Everywhere)