Jee-Han is immortal
His pact with Gnome stated they'd be together until his soul perishes.
The Existence Eater / Temporary Magician is Han's father ( or even mother )
Both characters are conveniently absent from the story, yet referenced periodically as to remind that they are relevant to the story. The mother part comes from her mysterious disappearances throughout the story, and the current mother with a discernible level might infact be a very elaborate golem.
- Maybe they are both his parents?
There would be tournament arc
The illusion barrier was created for fighting, and it's been hinted something's going to happen soon.
Plus, it's a great chance to see other Natural Ability users
Jee-Han will use his Life Drain ability to help or cure Hwan Sung-Ah
Her Black Demon's Invasion curse drains life force, and apparently her life expectancy is low even if she is given life force every now and then. However, once the Life Drain ability is levelled Jee-Han can use it to transfer life force, presumably spamming it like he does the Yunhon Soul Recovery. With this he can keep Sung-Ah healthy long enough to get his Soul Recovery to a high enough level to remove the Black Demon's Invasion altogether.
Hwan Sung-Ah is related to Jee-Han
She looks like the genderbent version of Jee-Han, and Jee Han father is actually dressed similarly like her father.
There will be an arc in which the Mana Farms come after Jae Han.
Jee-Han may have the ability to save. Even if he dies, he can return to a point in the past and try again.
Most RPGs have the option to save, and with that the ability to reload to the last save point at death, or even at will. If Jee-Han has this ability, he becomes nearly unbeatable.
His refusal to even consider raising Wis will end up biting him later.
Even worse, he won't raise Wis unti that moment cause he hasn't got the Wis to see how it could be beneficial.
- Jossed in chapter 67, he did raise his Wis.
Jee-Han is insane, or simply making it all up in his head.
Because it needs to be contributed. None of this is real.
Sun-Il is in love with Jee-Han.
He might just be, it kind of seems that way after all.
Han Jung-Sook (Jee-Han's mother) has been replaced by a robot, a clone, or a shapeshifter
Originally, Jee-Han couldn't see his mother's level (implying that she was at a higher level than him by at least 50 levels), but then he could suddenly see her level (in the teens) and she started behaving oddly.
Sun-Il will pull a face heel turn.
Because really, if you had been working hard since childhood and have your best friend beat you in matter of months and bragging about it, anyone would be tempted to pull a face heel turn on him.
Han Jee Han won't end up with anyone
It's probably more of Harem parody at this point. If it were dating sims, Han Jee Han is not really in anyone's route since he tried to built relationship (and have event) with every character.
- But isn't that how you get the secret harem option in some games?