I think from what I've gathered from the latest chapters Jumin is the snake demon spirit that was forced to become Muni's replica. Giyun is the real reincarnation of Muni but with extra baggage of ghosts, since the shaman pretty much latched on every ghost in the vicinity of the ritual.
Il-In of course is the past version of Yitae. Ghost Yitae on the other hand seems to be a missing piece of Yitae which was taken by Jumin to create ghost Yitae and prolly why Yitae doesn't think any of what's happening to him is real because a piece of him is missing, he doesn't have a connection to his his past life because that he's still not complete
Okay yeah this makes sense ty
Jumin = Long neck = fake ‘Muni’
- the blood of Muni that was spit out of the snake?
Giyun = real Muni? = multiple ghost posses him at times(?) = hates Young Master
- Reincarnation of Muni? Muni wanted to forget the past and move on tho. Are they separate or the same?
Young Master il-in = Bastard
- hated Muni and left him to die in the pit, but ‘fell in love’ with Muni’s comatose body..? Tried to resurrect him but as his ideal version
Long hair ghost/‘Yitae’ = imitation of Young Master made by ‘Muni’
- kind of his own self, not really similar to il-in tbh..
Mr. Jeong Yitae = Normal dude(?)/reincarnation(?)
- his body is being used as a medium or something?
I had to make a note because it was getting confusing tryna understand if this is incorrect/im confused pls lmk..