
Technically it isn't incest because both characters have not lived their whole lives with eachother so there isn't really that cultivated bond you would get from say, a step family when you were a child. Like, Sunwoo didn't even know about him til their families had dinner so obviously he would get a crush because he wasn't raised into cultivating this mindset of thinking jeunghyun to be his brother, so incest is clearly NOT present in the story. They are not related nor were they raised together! Sunwoo may act young but remember, he is a COLLEGE student therefore an ADULT so he knows his thoughts and actions and have autonomy over them like a normal adult.

the concept of guideverse is kind of lackluster to me, from what I usually see from guideverse manwhas, it's very traditional(?) in a sense that it reinforces roles of a heteronormativity of "strong masculine person" and " weak and feminine person" or in this case guide and esper which I find very concerning. Also I don't like how guides are somewhat useless other than to keep espers in check, like what do they do with all that energy they sap from espers? do they just purify it and bam they have all that stored energy or what?? They are portrayed as mostly weak and not very helpful other than the thing they are naturally able to do which to me is kind of weird especially when you consider the underlying heteronormativity within guideverse which is kinda ironic how guideverse is usually in BL. Also, arent guides also said to have superpowers??? So surely they must have some sort of way to contribute other than to just guide??? Also the villain to me, is very 1 dimensional and kind of cartoony in a sense. We don't really know much about him as to what drives him to make the city guard be the number 1, like thats it? that's not really a strong ambition to do allat inconvenience. Bro couldve done something else other than be a massive dick and the ex boyfriend was mentioned once just came out of nowhere, I completely forgot about him until he showed up LOL. I genuinely love it when ukes are cute and feminine but only in looks, if their personality is completely dogwater and their character is so helpless to the point where they have to have someone else help them which leads me to another point I don't like in Guideverse. Why are guides allowed to go in dungeons with no minimal defense system?? Like they can't even do anything to protect themselves and they're all huddled in one place and from what ive seen, not that much espers protecting them and isn't that like kind of a hazard??? ANDDD if theyre sooo supernatural, why are they literally just normal people who can calm espers down like???? that's not really supernatural, like yeah you can stabilize their power but like erm??? that's all?? Being a guide sounds like being someone's innate therapist who stops people from being self-destructive and stopping them from also being destructive to people around them, is that their superpower??? A therapist & counselor for the actual supernatural LMAOO????

Regarding the first part of your comment
I think it's just the typical bl/yaoi fan mindset (not yours but the authors)
Because to me I've always found the guideverse similar to omegaverse and now since you've brought this up, it's made me realise omegaverse is the same way
I think it only started to change when people found the concept of "a bulk strong guy" can be capable of being an omega
Idk if it's true but I only started seeing guideverse recently so I always assumed it was a new trope/genre?
Recently as in late last year though lol but given how long all the other tropes have been out then I consider it recently, but correct me if I'm wrong about that.
So I've just always thought that if we gave this enough time to age it'd become similar to omegaverse in that aspect. We're going to start seeing roles reversed. "Bulk strong guy" is the shy timid guide while a "feminine" person is the esper with the bold personality
(I also think I might've gotten the roles reversed sorry LMAO)

After seeing several comments with similar opinion about Guideverse. I realized, I probably don't have this impression because my 1st encounter was with a Shou Esper/Sentinel and a Gong Guide (both were OP. Gong was not a delicate guide and Shou was anything but meek).
The manga in question is "a guide to reincarnation" btw if someone is curious.
BRO IS GETTING A YEAST INFECTION