
Can someone spoils what is exactly "kim dokja's love" is?? Is it about yjh or about the girl??

Depends on interpretation
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However, factually
it's not a person but rather it's the personification. Like they(kdj/hsy) said, it's not to be taken literally.
In this case, it's TWSA that is his true love.
YJH is the protagonist of that story. If there's no YJH there's no TWSA. So basically the person he loves that most is TWSA aka YJH.

SPOILER AHEAD
KDJ's mother explain that pretty well. The person he loves the most is Yoo JungHyuk, but is not a romantic love, is because when he was growing, when he was being abused and all, the only thing that keep him from defeated was to read TWSA, was to read the stories of YJH, so he is the person he loves the most because he encourages him in his worst days.
This is actually my first time enjoying sex scenes in bl they are hot but in a cute way unlike in other bl they just do sex and dirty talk each other so i partially skip that part..
Fr tho. The others just kiss kiss then fwop fwop fwop. This one felt intimate and deep. They're really compatible and I'm so single sobs.
Ikr i can feel the sensation