Sonohara Anri is a girl who notices many things. She may be rather shy and timid, but despite her insecurity about herself she understands people very well. Or maybe it's because of that uneasiness she's better aware of her surroundings.
Whatever the cause, it did let her recognize that same uncertainty in Heiwajima Shizuo. Behind those dangerous fighting skills and aggressiveness he's actually somewhat kind, in his own brutal, blunt way. And once she realizes that, she's no longer afraid of his temper; rather, she thinks it's kind of cute, the way he and the informant fight. He's like a little boy denying his crush, not realizing the reason why he feels so frustrated and anxious around the girl. Not that she would ever call Orihara Izaya girly. Or tell the traffic sign-wielder of her thoughts.
She's perceptive, not stupid.
And she definitely wouldn't tell Orihara how adorable he is when taunting Heiwajima or saying how much he hates him. If the bodyguard had braids, Anri's sure Orihara would be pulling them at the playground.
She notices the same electricity around her friends; in Kida's protectiveness of Ryugamine, and in how he's always touching him or at least around him. In Ryugamine's jabs at his jokes and in the admiration he has for his best friend. She notices it, and she understands.
Even if they don't.
It's why she never says anything when they compete for her love. Like Harima, they are using her to get each other's attention. She knows it's bad of her to keep quiet, because they could be so much happier together, but she won't speak up. She can't bear the thought of being taken advantage of, even unconsciously, especially not when she'd hoped…
Because of this comprehension, she isn't surprised when both Kida and Ryugamine ask her out.
"I-I am very honored, b-but I don't want to… choose b-between you two…"
-I don't want to stand in your way-
"Well, then there's no problem. You'll go on a date with the both of us! That way you won't have to," chirps Kida in his ever-exuberant voice, "two for the price of one-"
"I-it'll be fun, Sonohara-san… S-so… please?" Ryugamine cuts in successfully, for once too nervous to remark on his friend's antics.
She is a bit surprised though, when the evening turns out wonderful, not awkward at all. Even the Russian sushi tastes better than expected, and that same energy always surrounding the two engulfs her too. She's nervous, but the fluttering in her stomach isn't entirely unpleasant.
And all the while she tries to talk some sense into herself, because this isn't meant for her, and it certainly isn't real, but her feelings overrule all logic at the moment. Her crush, for who exactly she isn't sure anymore, sweeps her away, and she decides to just enjoy this now, accepting the fact she'll get hurt even more later.
Shock settles in though, when she feels the daring lips of Masaomi, as he asked her to call him, softly on her own. At the top of a decaying building, long since overshadowed by neighboring newer flats, the look of bewilderment turns into one of perplexity as she witnesses that same mouth lean into his friend's seconds later to repeat the act. Masaomi nudges him slightly, and Ryugamine, no, Mikado, closes the space between them shyly. He isn't as bold as Masaomi, but just as gentle. This time she's actually prepared for it and presses a hesitant kiss back.
Yes, Anri notices a lot of things, like how warm Mikado's body feels as he wraps his arms around her, and how comfortably they both fit into Masaomi's embrace.
And as they watch the setting glow of Ikebukuro's sunset, she wonders how it comes she never noticed before.