THIS is such a wonderful take. Lowk almost convinced me but I just can't shake off the part where an elf told chef that only elves can see spirits and sometimes elves can't even fully see these spirits but chef does. With the photo at the end, it made me think that it's actually his grandma and he actually has elf blood in him — the reason why he could see spirit and he naturally has high affinity to be able to fully see them ╮( ̄▽ ̄)╭
That makes sense too, the only reason I couldn't get behind him being a quarter elf was because his sister can't see Tori. If he is a quarter and can see spirits so is she so in theory she should be able to see Tori. So that kind of led me to the maybe difference bein that theoretical blessing. Yes, the white wolves' mark should help but he could see Emilia's bird before that. There had to be something besides his experiences after he found that realm that gave him the power to perceive spirits. A blessing making him loved by the spirits felt more right than wrong I guess. (〜 ̄△ ̄)〜Like I said this was just my mind spinning off after playing catch up on chapters I missed. I admit I stared at the photo for a while and short of my own theory the only thing I could come up was the obligatory family secret guardian angle. Had to disregard that because the few interactions with the parents made them out to be ignorant of the other realm.
I'm hoping it doesn't drag on but at the same time I don't want it rushing to a conclusion. The only thing i know for sure is Mona is now going to his world. No clue when or how but she's definitely escaping. Now that we know other realm dwellers can cross over it would be a tragedy to not let her have food and play dates with the villagers. He will literally have to roll her back through the portal once she discovers snacks from Korea

The picture at the end actually made me feel that his grandfather definitely had been to the other realm and had in fact brought an elf back to Korea. Yes, there's a certain intimacy between them with the pose, arm around shoulder, but I didn't actually get a lover vibe. The pose felt like how I hung on my friends of the opposite gender so there's affection and love but without the messy romance angle. The physical distance just felt too wide for it to be lovers for me I guess. Though thinking more about the Grandfather's behavior maybe they both liked each other but couldn't be together so they settled on friendship. On Grandfather's side he never left because he wanted to protect her forever and be close to her since he couldn't be with her. On her side the clothes gave me a nobleman vibe maybe she realized that a human lifetime isn't compatible with an elf's life. So there's probably another treasure somewhere with her and she will see our chef and picture his Grandfather. I could even see her giving him a blessing as a child heck I'm betting Emilia and our little sister have the classic run in. Or better yet they get to travel to the other realm as well. Definitely a weird way to spinoff from a picture but that's just how it felt to me in that moment looking at the picture.