First off, this was such a cool project for Idol Factory to take on. The thai mythology aspect was interesting and very unique as that's yet to be done in a BL production to my knowledge. It seems that I may have an unpopular opinion about this series as I'm not rating this a 9.5 or 10 stars but I've gotta say that I'm so glad that IDF decided to create this. Hopefully it's another step forward so that we'll get more dark and complex BLs in the future!

I loved the opening action, the fight scenes were really well done and the shots are pretty aesthetically pleasing. I had no issue with the acting. The character are likeable enough and both couplings had good chemistry as well. This series has so much to include, there's the crime, the police investigations, the fight scenes, the mystery, the mythology, the romance and the lore to be established about Tharn's abilities, as well as the past lives aspect. Nevermind the human relationships part with this big cast of characters. That's a lot to juggle in one show especially considering that this is only IDF's third production, so big props to them!

That being said, beneath the novelties and all of the aspects mentioned above- the flashiness of it all, if you will- it's decent but is falling flat for me. The show doesn't seem to know what genre or tone it wants to be/hold and shifts it every episode or so. At multiple points, it was boring and kinda draggy and then sometimes, it's just really really CAMPY out of nowhere?? Sure, that could be chalked up to the contrast and sum of all of the different aspects that The Sign has set out to include and while it could surely be smoother, that's not the issue at play here. At first, it keeps it interesting but it's not consistent enough and didn't necessarily feel the most cohesive to me; it was weird. It feels like there's different directors alternating between the episodes.
The writing and storytelling isn't great, it's the same issue that I had with GAP; it's trying to do way too much without the quality writing aspect that's needed to bring it all together for what the production really deserves. The characters are likable but not memorable. They don't have that much depth and I find them to be underdeveloped which in turn means I'm not that invested in their stories. I'm definitely someone who enjoys character driven stories so I need the characters to be compelling enough so that I can connect with them and care more about their storylines.

The CGI was great especially for the budget of the production but the costumed mythological flashbacks felt like an odd 'stage play' (as someone else had mentioned in the comments while airing). It really took me out of the scenes and distracted from their importance; it was also frankly a little painful to watch. But I've gotta say that The Sign has really mastered the art of strategically blocking NC scenes which some of the bigger BL production companies have yet to master *shade intended*.

My favourite characters were probably KhemThongthai, Nee and Nee's cat, Namami. Namami is my favourite. But as of right now, I've currently lost interest in The Sign after episode 8. This series is just really missing something and I can't quite put my finger on it but I'm fairly certain that it has to so with the writing. I do like this series so I'll probably pick it back up when I'm more in the mood to watch it. I am happy to hear though that so many people here are enjoying this show because it does have a lot to offer and will keep you visually entertained, if that's what you're looking for!
This show has a handful of really good concepts, so much potential and I could see the artistic intentions behind some of the storylines and production choices, but unfortunately, it just wasn't all that to me.

My rating would be about a 7-7.5 out of 10 stars.
(If I do pick this title back up again, I'll make sure to edit this review :))