My Twin Stepsisters Are Way Too Yandere!

Aoi Tachibana was faster than the rest in noticing changes.

Little changes, small changes, sneaky changes.

Kuro checking his phone more and more often

Kuro smiling to himself while texting.

Mina being unusually quiet around him.

Everyone else was not making connections.

Except Aoi.

And she understood.

It occurred during breakfast.

Akari complaining loudly about her homework, Daichi reading the newspaper; half-asleep, and Shizuka cheerfully making too much food again.

Meanwhile Kuro, under the table, was eating his toast quietly while checking his phone.

Suddenly the corners of his lips turned up a tiny smile.

A smile that you would hardly notice.

But Aoi did, instantly.

Also, across the table, Akari saw it.

Everyone stopped talking.

Akari slowed down her breathing and narrowed her eyes.

"Who are you texting?"

Immediately, Kuro put the phone down and locked it.

"No-one."

"That sounds suspicious."

"Is it Mina?" Akari asked, without hesitation.

That was it.

Kuro hesitated just long enough.

"IT’S MINA!!" declared Akari, pointed at Kuro.

Daichi lowered the newspaper and looked.

"Who is Mina?"

"Dangerous gyaru woman," Akari replied, without hesitation.

"Kuro," Akari sighed.

Aoi was sipping tea and watching him closely.

Inside was a knot twisting uncomfortably in her stomach.

Because recently Kuro had been smiling differently when he received a text from Mina.

More relaxed.

And that scared her.

At school, this difference was becoming even more obvious.

During lunch Mina sat down beside Kuro casually like usual.

But today Aoi saw a difference.

Mina was not performing .

Normally when she was with Kuro she would tease him very loudly, steal food off of his plate, invade his personal space and embarrass him publicly.

But now it appeared that they were operating off of their own separate beat or rhythm.

Their conversation flowed effortlessly.

"Did you really stay up until 3 AM again last night?" Kuro said softly as he opened his milk.

Mina gasped.

"You sent me a total of 23 text messages about alien conspiracy theories."

"Research is important."

Kuro sighed softly.

"Go to bed earlier."

"Only if you promise to stop responding to me."

"That’s fair."

Then Mina laughed.

And for a moment Aoi realised something.

Kuro laughed back at her as quickly as she laughed at him.

Without hesitation

Only naturally.

That is a dangerous thing.

Over the rooftop Akari observed something about her boyfriend’s descent as well. However, Akari’s reaction was immediate unlike Aoi’s.

"Nope." Akari blurted out. Mina blinked as surprised. "What?" Akari jumped right in between.

"You are getting a bit too comfortable!" Mina grinned instantly. "Oh-ho?" Kuro also sighed out of psychological exhaustion.

"Please don’t get started on this before we finish lunch." Too late. Akari crossed her arms dramatically.

"You are texting him every night now!" Mina became slightly stiff with surprise.

"HOW DO YOU KNOW??" Mina whispered loudly at Akari while pointing to Kuro. "He’s smiling at his phone like an idiot." Now, that is some serious damage to Kuro. Kuro almost choked on his tea.

"NO I DON’T!" Kuro responded.

Aoi turned away very quietly because Akari was indeed correct.

That afternoon, Aoi found herself alone in the library alphabetizing books or at least pretending to do so.

Her mind would constantly drift to Kuro and to Mina, and back to the connection they were developing, and just as unexpectedly...

Rika appeared walking nearby with a large selection of manga.

"You noticed too?" Aoi said silently.

Rika calmly adjusted her glasses. "Kuro-kun and Mina-san.".

Aoi was looking downward at the books quietly.

"Yes."

Rika appeared to be smiling slightly.

"He appears to be at ease with her."

That word once again.

Comfortable.

Not an excessive passion. Not chaos of emotions.

Natural bond of connection.

And somehow that scared Aoi more than anything else.

Because she knows Kuro well enough to know, he has a strong appreciation for peace.

And then quietly Rika continued speaking.

"Mina-san is very outgoing in her laughter. She is loud when around everyone else."

Again, she was placing another book on the shelves quietly.

"But with Kuro-kun,"

Aoi finished the thought in her mind:

She becomes honest.

Silence lightly enveloped the library before Aoi spoke softly .

"She is good for him."

The words pained her to say.

But she felt true concern about the statement.

Rika looked towards her cautiously.

"That makes you afraid."

No question about it.

Aoi shut her eyes for one brief moment.

"Yes, a bit."

That was more truth than was planned.

So that night Kuro came home late after he helped Mina with her homework again.

Akari was shocked when his body hit the house on the way into the living room first.

"Hey."

"Why do you sound like a police officer?"

"Because I believe your activity is suspicious."

Kuro turned and did not respond to Akari and lifted his feet to put them inside the door, so he was tired, then he hesitated.

Aoi was sitting by herself on the couch, reading quietly.

But the second Aoi noticed him enter—

she looked at him softly.

And they exchanged glances for just a moment.

And all of a sudden—

Kuro felt that same warmth spread through him again.

A dangerous feeling.

Because even though he had been with Mina for quite a while Aoi still had that effect on him instantly.

And then Aoi whispered out.

"...Welcome home."

So simple but sweet and caring.

Kuro could feel himself begin to relax.

"...I’m home."

Across the room Akari was watching them both, quietly.

Then she flopped down, face-first onto the couch cushions.

"...I hate love triangles."

No one disagreed.