As a member of a system myself, I can say that it's not quite the same as DID and they are more so separate beings. Giovanni himself is different from Jio, however their assimilation comes more from that it appears that every dungeon technically has the same souls stretched across them in a sense. So Giovanni and Jio share the same soul wavelength, like how the color blue would be perceived as blue in both universes even if it was technically named different, however Giovanni himself says that they are different people. They are able to assimilate only on the (presumed) assumption that Giovanni himself is dead.
It appears that through mutual agreement, Jio absorbed Giovanni's soul to become part of him and allow him to persist even while dead, but it's not quite clear if that means that Giovanni and Jio share the same body now or if Jio is simply shifting into Giovanni's appearance when it comes to things that remind him of his own world (like the sea and healing the vendor)
Thank you for your reply! Definitely cleared some confusion!!
Hi hi! I’m just a bit confused? I don’t understand the whole root and garden/gardener stuff. Also does the persona thing function like alters in DID or are they two distinct beings that go beyond being an alter? Is it apart of him now, or is he influenced by the other gio? Please help!!