I'll try to provide answer the best as I can, hmm as far as I understood he was really an ordinary human before the great catastrophe came, just quite apathetic to most of things... But he became one with the origin when he awakened.... the novel had these statements in chapter 19
""Seo gio had very crazily, unexpectedly merged with the origin during the earth rebirth process, rasing the level of his soul
This was a mutation with miraculous probability that is difficult to observe in such a small dimension as earth"
And
"Meanwhile, in a truly unbelievable and mind-bogglingly miraculous miracle that should never have happened, on that day that was supposed to be the last day of the Earth but wasn't, Gio unknowingly merged with the Source and evolved into a possessed portrait..."
So yea I guess he's not human anymore I guess hahahaha
To the person who commented earlier, apologies your comment vanished, didn't know comments gets deleted when editing the post
But regarding if Gio is a human or not, as far as I understood he's just a normal human pre catastrophe, he merged with the origin/source when he awakened, as per chap 19 of the novel
"Seo gio had very crazily, unexpectedly merged with the origin during the earth rebirth process, rasing the level of his soul
This was a mutation with miraculous probability that is difficult to observe in such a small dimension as earth"
Nvm i thought comment vanished it was just mangago messing with me lol...
But yea tbh, if we gonna dig deeper into the spoilers.... gio doesn't remember it right now, but he didn't become a portrait immediately when disaster came, he lived with his students for some time, he awakened godly painting skills and his students created a cult and tried to set him up a god, then he got attacked by fanatics and was left half dead while his students were away.
gio's portrait was actually his attempt at creating a clone of himself lol
students ate a part of him and gained a part of gio's abilities and created system in attempt to keep gio with them and to support awakeners in exchange of their memories of gio, then that gio's portrait became the system afterwards
From what I roughly understood....I think half dead Gio then ended up in the portrait trying to recover, but a part of him split up and worked as a system, it took him 30yrs to recover and regain his identity as gio
So yeaaa, I'll leave it to you to digest what gio is hahahaha
Tbh same hahahaha, but well they were barely an adult at that time 17-18yrs old I think, didn't have any reliable adults around them aside gio during that time, and they were highly dependent on gio and revered him some kind of a perfect being as well so they didn't wanna lose their teacher hence were crazy enough to do this crazy stunt
They did, actually only 3 out his 4 students did the deed, one of them didn't do it, and remembered everything
And the three of them are the current symbol of eternity and are s class hunters, namely :
-head of the association - inherited the Promise skill (the skill that was used to create system in exchange of memories)
-guild master of top one guild justitia- inherited the friend skill
-guild master of top 2 guild- also the very first gardener), inherited the punishment skill
one is just c rank who serves as the current president of the korea, the one who remembers the whole fiasco
Gio eventually ended up meeting them one by one, h originally he wasn't really interested in the forgotten memory, tho he did realize his current memory wasn't correct and that something happened to him that made his students do something extreme where they needed to use the promise.
Then the last "Gio" - George, wanted to cause a huge mess so he roped in the first gardener guy into helping him cause a mess in earth. first gardener guy was first person to start remembering and regretting the past so then now he wanted to destroy the symbol of eternity, because of that it caused the system to start having error. Since system was created with their memories of gio as promise payment. so yea getting back the memories will invalidate that promise.
The association president was the next one to remember, originally she the most level headed and indifferent about the memories, then she entered the dungeon of George she started remembering the memories eventually regretting it
GM of justitia remembered everything after the promise was broken
Omg, thank you! All my curiosity and theory was answered! My theory was that Jio was some kind of god but just forgot and thought that he was just human. I mean I was half right cause Jio was treated like a god. I did wonder about the students but kinda thought they all died or something cause they were never mentioned again(that’s why the god theory). Nice to know some survived! Though most became…well… yeah
But the whole self portrait to make a clone is wild.

I'm finally done binge reading the novel, it was a fun read hehehe can't wait to see the future characters in webtoon (*˘︶˘*).。*♡ I really hope this webtoon stays until the end of the novel