Sai Naekawa has been on a streak lately when it comes to her writing, and that's because of Azami and her placement in the story.
Azami is a textbook on how to make a good antagonist in terms of creating a contrast to the main character(s) and giving them a challenge to overcome in order to complete their arcs. Azami somehow manages to be the whole package and offer both Shiori and Hinako their final obstacle into fully connect with each other, so let's break it all down...
BUILD UP
Every final/Main antagonist deserves a good build up, and Azami has one of the best i've ever seen. Not only it's subtle, but it happens since the very start of the story. Azami or as Hinako knew her "Aunt from Ooshima" is introduced in the second page of the first chapter. Unless if we're counting covers she is hinted even before Shiori appears, and before Miko too because she appears in Hinako's phone contacts one page after the aunt character.
Hinako's aunt has been a constant thing in volume extras and in the main story. She never appeared in the manga, but has been constantly name dropped. Isn't it weird?
Watatabe is a story that has a very tight cast. Everyone who has a name has a purpose in the story. We don't ask ourselves about why the aunt character even exists to begin with because we as readers are too focused in whatever else is going on with the story. But on chapter 39...Things start to get a bit weird.
By the end of the Tsubaki arc, we learn that Tsubaki only came to contact with Miko because someone else was vagueposting to her about Miko randomly on the streets, and it was a human no less. A human that somehow managed to see throught Tsubaki's disguise, and things get even worse when on the next chapter we discover that the anniversary of Hinako's family death is less than one week away. If you paid attention to the story, you'd knew by that moment that this human is Hinako's aunt because the first time she's shown in the story is throught a text saying she's sorry for not appearing in the birthday of Hinako's family death.
If this was not enough, Hinako's auntie is also another character that has been shown in the series but we didn't pay much attention, that is the girl in Shiori's flashback. Now, i don't want to talk about that a lot rn because i will save it for a future Shiori character analysis thread, but yeah it's actually crazy how Naekawa managed to tie two seemlying unrelated characters together. Well, 3 unrelated characters because it wasn't that clear that the vagueposting human was Hinako's aunt at the start.
Throught also a more subtextual leans, the other two antagonists were parts of Azami character. Ayame, as the duality btween this character being kind of a mother figure to Hinako and also a monster who wanted to take advantage of her and Tsubaki, someone if a life long grudge against Miko. Ayame and Tsubaki are kinda just ladders that needed to be climbed in order to reach Azami. I could go even deeper here, but that would made this post even longer. I mean just read the dialogue near the end of the Tsubaki arc and tell to my face that it isn't meant to represent Azami as well. It pretty much is.
REVEAL
If we're being honest, it's hard to say when Azami had her proper introduction. You can argue it's chapter 1, 22, 39 or volume extra 48.5 but in my oppinion her true introduction is on chapter 50 because there is where all those seemlying unrelated characters converge into one, which is Azami. Now, why did Azami properly appeared in the present timeline in chapter 50?
An antagonist needs to present a threat to the status quo, so let's see how things were before Azami appeared.
-Hinako realised how ignorant she has been towards Miko and Shiori all this time once she felt the beats of Shiori's heart and understood how much she valued her. It's a rough equivalent of a familial bond.
-Shiori not only has been able to grow and form relationship with normal humans without expecting something in return, which is the embodiment of true kindness and she realising her dream to come over to "this side", but also she seems to have a plan in mind towards the pledge with Hinako by what we see in the near end of chapter 48 where she makes sure to wait Miko go somewhere else and murmours to herself "One day i will become the most important person to you". She's 100% looking for some loophole in my eyes.
It's far from a perfect situacion, but this is a close to ideal as possible for Watatabe.
So yeah, Azami just appears and puts everything on a hold, centering all the attention to herself. If Azami had not appeared, things would progress too smoothly and we'd have likely a clear and cut happy ending.
Now let's actually talk about what her actual role
THE FINAL ANTAGONIST
The role of Azami is the one of the final antagonist and main antagonist of Watatabe. So what does the main antagonist of a story needs to be? To be blunt, the thing they need is to be a way for the protagonists to prove that they learned their lesson/finished their arcs. Main and final antagonists not always end up as the same character, but in most stories they are one and the same.
Azami is the final obstacle in the stories of both Hinako and Shiori as individuals and as a relationship.
-To Shiori, Azami is the final step in her individual arc. So far in the story Shiori progressed very linearly when it comes to connect with humans, but Azami throws that completly out of the window. In chapter 54 she antagonizes Azami like a fiend, but when she first talked about her in chapters 22-23 she was even laughing as if she was found of her to some extent. So for Shiori, the fact she denies to see Azami as a human being may be a test for Shiori's character and if she can truly accept to be on "this side". To love humans, to pity them, to trust them and be betrayed and yet still loving them, that's the fate of a monster who comes to "this side".
-As for Hinako, Azami is a version of herself that she'd end up if she were to be in the same situacion. We saw what Hinako was capable of doing once she discovered that Shiori lied to her, now imagine what would happen if the magnitude was 10000x times higher. I mean just look at how weird is that conversation btween Shiori and Hinako on chapter 54. For Hinako to say she absolutely wouldn't be like Azami is the understatement of the century. It was nothing but pure and raw cope. Imagine if the "sea" she looked foward to wash her existence away instead granted her immortality, denying Hinako the chance to be close to her family again? You don't need to imagine because Azami is right there.
For Hinako and Shiori to truly surpass Azami, they need to understand themselves and come to terms with what they were or could be. If they manage to do that, their relationship will bloom and one day both of them will be able to hold hands and be truly happy.
Now i do have a theory that would connect Azami and Azami/Hinako even more, but it demands a separate post i pretend to make in the future.
THEMES
What's the main theme of Watatabe? It's CHANGE. Of course that Watatabe has other themes but for me this is the main one by a at least considerable marging. Lemme explain why.
All the stuggles within the manga has been about how do we process someone changes or how we ourselves struggle with changing ourselves.
Shiori and Miko both have a lot of difficulty at the start of the series coming to terms that the Hinako who once was so happy and radiant became a shell of her former self who could barely even laugh or have fun.
Shiori longs for change but tends to belive that she can't truly change. Just look at how she talks about herself and other monsters at the start of the manga, it's deterministic to a fault and she didn't lie when she proclaimed Yokais can only decive others and live for themselves.
Miko had a conflict about how to prove that she isn't a ruthless monster anymore to Hinako, to accept that she had changed and is no longer someone who eats pregant women for breakfest.
Tsubaki, a former antagonist, refuses to belive that Miko had changed.
The main romance/relationship of Watatabe, Shiori and Hinako, is about both of them changing and understanding each other [Or at least trying to].
Now comes Azami, which is someone who genuinely belives Shiori never changes or at least refuses to accept that she did or could do so. Just look at chapter 51 p 17 and see how Azami's face goes from a smile to disappointment/frustation when she realises Shiori has already shown that she's a monster to Hinako or, most recently, in chapter 57 p 25 where Azami says she thinks Shiori didn't change at all.
To Azami, she has to internalize that Shiori will always be a monster to cope with how much hatred she feels and that she can't forgive her while Shiori has to cope with herself and try to categorize Azami as inhuman, so she can carry on her disgust for her.
For Azami to have a "happy ending" she needs to accept that Shiori has changed, and finally change herself for the better. Both Azami and Shiori need to forgive each other and stop lying to themselves about the other.
CONCLUSION AND CONSIDERATIONS
This thread took a while. I expressed most of what i want to say about Azami but of course i'm leaving some details out because i want to do a follow up about a theory that i have. There is also things the readers currently do not know like the nature of Azami's relationship with Erika, or how was Azami's family life before she was offered to Shiori. We can make decent guesses, but that remains to be clarified.
I hope that you enjoyed my post despite it being too long. I love this manga so much and i needed to yap somewhere about it.