Author's Note: This fic references both the Disney and Hans Christian Andersen version of the Little Mermaid.

"I want an eternal soul."

At Izuku's words, Katsuki has to do a double-take.

"A what?"

"An eternal soul," Izuku repeats. "Like how humans get one after they die."

Katsuki rolls his eyes.

Izuku looks away.

Katsuki clicks his tongue.

"It's just the two of us, hanging out here on a beautiful day, and you're thinking about you want an eternal soul?"

The sun cuts through the water, through their sea, as the pair of mermen stare up at it as they lie sprawled out on a wide smooth rock that's relatively close to the surface.

"We're merfolk, Izuku. An eternal soul…We… don't exactly get that."

Katsuki closes his eyes. "We turn to sea foam and cease to exist when we die."

"Can't we change our fate, though?" Izuku asks weakly, hope in his eyes as he stares up at the sky. "Wouldn't it be amazing to have an eternal soul that lives on in heaven, like how humans get one?"

"Your obsession with humans needs to stop, Izuku."

"I can't help it. They're so—"

"They're not us, Izuku. How many times do I have to tell you that."

Izuku lowers his head, and Katsuki sighs.

"And you need to stop dreaming so much. Like, I can tolerate it because you're my closest friend, but…"

"I want an eternal soul!" Izuku repeats. "More than anything!"

"I think what you really want is for someone to love you, Izuku, but."

Sarcasm then seeps its way into Katsuki's voice. "Keep talking about humans all the goddamn time. That's the quickest way to get into a mermaid's heart!"

"You don't understand." Izuku mumbles. "Humans are beautiful."

The sun flowing through the water, basks itself onto Izuku's delicate form.

And Katsuki wishes he could look away.

Not as beautiful as you are, Izuku.

When Katsuki and Izuku part ways after that, Izuku's first instinct is to visit his underwater hidden grotto, where he's collected a wide array of human treasures through the years.

But instead, he finds himself swimming towards the surface.

He's not a stranger to the surface— and obviously, no stranger to things that are human, but in spite of that, the human world never ceases to amaze him.

Now if only he could actually befriend a human, for once.

"I can't get him to stop thinking about humans," Katsuki mumbles to himself irritably as he swims home, "what a good friend I am."

"Of course, I've always viewed him as more than a friend, but… he can't get his head out of dreamland and focus on what he has as opposed to what he could have."

"It's what makes him beautiful, but… dammit. He belongs down here, under the sea, with all of us. Why he can't he just see that?"

Katsuki sighs. "Stupid Izuku…"

"You can dream all you want, but when it really comes down to it, the sea is where you belong."