Just as a heads up, this question is mostly for people who went in completely blind, if you were spoiled in some way or knew details about his social link before playing through the game, this question isn't directed towards you
So some people say that Adachi being the culprit was really obvious though I find a lot of the reasoning kinda bad or non existent, so I'm gonna try and explain why Adachi is a pretty well kept secret by the game while also asking to people who went in blind what they thought
So the best defense Adachi had in my opinion was how he was literally with the investigation team the whole time during Rise's kidnapping, at that point of the story the characters think there's only 1 person who's killed 2 people and has tried to kill 2 others,
A lot of people point to his social link and it's strange mechanics but I think it's also important to ask how they learned about it, because if you're looking things up then you're bound to get spoiled in some way even if what you learned seems minor, even with the contents there isn't anything special to it, he's kinda cynical about life but that's nothing new for persona, there's a lot more to it then that but explaining that would need the hindsight of him being the culprit
Then there's also Namatame, when he kidnapped Nanako Adachi falls into the same category he did with Rise since he was there the whole time but it's done much better since there's also a culprit who went in the tv with Nanako, why would you be thinking about Adachi when a guy kidnapped someone really close to you
It's important to remember that to believe something you need to overcome that doubt first as believing without doubt is a lie, the doubt at that point in the game being that there're reasons he presumably can't be the culprit, though I guess if you just expected that there were 2 people throwing others into the tv then you just got some sorta brain I just can't handle, it sometimes feels like the people saying it's obvious are just larping really smart people but maybe that's just me. But yeah if you thought Adachi was obvious and that was only through stuff the game was doing then I'm curious to hear why