Zalgo is able to manifest himself partly into a space connected to inhabited dimensions. This space is known as the Corruption Zone, and it will take on the appearance of part of the inhabited dimension in question, working as it's "Shadow", so as to fit with it's theme. The universe itself is inhabited by soul creatures, who are technically recognized as the 'evil' versions of some residents of the dimension, who have slightly mixed with the power of Zalgo in order to become the "Shadows" of those people. Defeating a Shadow will lead to the acceptance of that evil and will provide the person with a powerful element which is based solely on being a power strong enough to defeat the fragment of Zalgo, as the fragment in question would have a number of his own power put into it.
- Shadow Zoshi was slightly inhabited by the soul of Xavier Z, or XoshiZ. Upon defeating Shadow Zoshi, XoshiZ was released or something.
- Shadow Ludicrine was slightly inhabited by part of Cut. Upon Shadow Ludicrine's defeat, Cut was released into the dimension or something.
- Shadow Samuel was inhabited by part of Equiusamuel*.
- Shadow Lazro was inhabited by part of Future Lazro from the Doomed Timeline, namely the Devil side of him.
- The Corruption Zone itself manifests as part of Ludus, being it's "Shadow". It's realm contains all the horror, death, and destruction that ever existed on spaces of the planet, which is why it is the macabre location it appears as.
- Shadow Rev was based off of a being displayed in his future.
- Shadow Luna was inhabited by a being displayed in her future.
- Shadow 02 was inhabited partly by a darkened version of her future self.
I think that's it for this idea, unless I'm missing something.