Inspired from the prompt Children Ranka notices a few differences about his precious child.
Ranka noticed something different about Haruhi these days. She went out more. She fussed less about the girly clothing that he tried to force her to wear. She stayed up later to finish her homework, and he could only assume that was because she stayed out later after club. Ranka had tried prying information out of Haruhi, and that didn't work at all. She merely told him that she finished everything that she needed to, and that what she did otherwise was none of his business. He didn't give her all the details of his life.
And so Ranka, much upset, called Kyoya. Kyoya commented that Tamaki had also noticed a difference in Haruhi, and was very concerned as well. Tamaki, however, was too afraid of Ranka to call him and ask if anything was wrong with Haruhi, for fear of being blamed for whatever it was that was wrong. And what both Kyoya and Ranka thought, but neither said, was the pure absurdity of Tamaki claiming Haruhi as his daughter annoyed Ranka to no end, and both knew that Ranka thought Tamaki a fool
This of course wasn't the answer that Ranka wanted.
It was then that Kyoya suggested that perhaps Haruhi was growing up a little. And then Kyoya hung up the phone.
Very much concerned Ranka debated calling Kyoya back and demanding to know what was wrong with Haruhi, but he decided that if something were seriously wrong, then Kyoya would have said so. Much later in the evening when Ranka caught Haruhi daydreaming, a cup of steaming tea in her hands, he understood.
His little girl was taking a step out of her childhood and into the adult world.
His little girl was in love.
He wasn't sure he could handle this. Haruhi didn't talk to him, didn't confide in him – if she needed guidance in the way of love, who would help her?
Ranka frowned. In the morning he would be calling Kyoya. Kyoya would know what to do. Kyoya would do anything for Haruhi.