Why aruani is going to be the only ship standing..
Both out of three man groups.
Both give what the other lacks. (Annie in emotions, Armin in fighting. I think Annie helps keep Armin grounded, just as Armin helps Annie stay standing emotionally.)
Both are empathetic. (Annie hides it, but she definitely is.)
Both want peace. Neither likes fighting. Annie was taught to fight at a young age for years, everyday. She didn't enjoy it. Armin, well, he was actually close to failing the scouts due to his lack of physical prowess..
Annie confides in him. I think her biggest fear is that she's a monster, and in chapter 132, or 133, she tells Armin that he only visited her because he's a good person. And why would he waste time with a monster like her?
Armin never told on her, even when he knew she was the female titan.
Not once, not twice but three separate times she stayed her hand in killing him.
Armin never forgot her. He always visited her. Their relationship stayed building even when she was in the crystal, slowly before she went in, and steaming ahead when she came out.
Armin takes Annie for Annie. He understands why she runs in chapter 133, and he doesn't fault her for it.
Armin though, is a big factor as to why Annie goes to help the others in chapter 135. She doesn't want to have regrets.
Like I said, this couple is trekking ahead and has been doing so throughout the entire series. Even when Annie wasn't around Armin thought of her. He visited her in her crystal prison, all the time for God's sake. And! He became the colossal titan, taking memories from the man who loved her as well. Now, do I think Armin contracted feelings for Annie through these memories? NOPE. It doesn't work like that. I do think though, Armin has learned a great deal about Annie through the memories of Bertoldt. He gets to see why Annie did what she did. And how she had no choice, really.
Mikasa realized Annie loves Armin in chapter 133.
"When did this start?" The answer is years ago.
They need to come full circle now. And Annie is getting there, now Armin needs to as well. He needs to run and Annie needs to be the one he's running to. Their ideals aren't cemented yet, they're still ever changing, growing, and taking final form. And I think that's why Isayama wanted to show it now, after leaving tiny bread crumbs. Cause, isn't that what falling in love is? Breadcrumbs of information about the other person you hold dear?
I think Annie and Armin will build what they've longed for.
