The first message Madara ever gets from his soulmate is a series of jagged, angrily precise characters that appear on his forearm with startling speed, written out in deep blue ink.

I hope you don't mind marrying a murderer, because I'm going to kill my brother.

For a long moment, Madara just blinks at the words. He's ten, dragging himself back from training near the river, weary right down to the bone and fed up with the limitations of a child's body. There are twigs in his hair, bruises all over his skin and blending in with the healthy coating of dirt, and his temper is fraying. Of all the times to get a message from his soulmate, this is probably the worst.

In the spirit of this, Madara's brain-to-polite-society filter glitches, and he grabs for his ink and a brush. Finding a clear patch of skin is a little harder, but he manages.

Well, if you're sloppy enough to get caught I'm not sure I want you anyway.

It takes about seven seconds for what he's written to register, and by then it's far too late to wipe it off and hope his soulmate hasn't seen it. Madara curses himself, dragging a hand through his tangled hair—and really, that's fantastic, his first words to his soulmate blatantly state that he won't like them if they're not a good enough murderer—

Cool ink against the skin of his arm, and Madara looks down to see, I'm debating the merits of three main plans, and I have two more for backup. Plans one through four make it look like an accident, and I will act appropriately grieved.

Before he can stop himself, Madara laughs. That—that's fantastic, actually. He waits for the ink to fade, then sets his brush to skin again and writes, If you're looking for a place to dispose of the body, a river with a strong current is always a good choice.

There's a pause, and then his soulmate writes, Noted. And appreciated.

Madara gets the feeling his soulmate doesn't just mean for the suggestion. He smiles down at his arm like an absolute fool, then drags himself back under control and answers, Of course. Can I ask what he did?

The response comes immediately, with a sharp slant of furious incredulity to the characters. He broke my favorite sword trying to do "cool moves".

Madara's future brother-in-law is definitely an idiot, it seems. He winces a little, feeling a flicker of sympathy—at least Izuna, with all his cheer, knows when not to act the fool, and when holding Madara's weaponry is one of the main times.

I will support you in all of your many life choices, he tells his soulmate. Especially this one.

Another pause, and this time the characters don't have the same sharp, almost hostile precision. Thank you, his soulmate writes, and then, after an even longer hesitation, I'm Tobirama.

Madara stares down at the name for a long moment, trying to breathe around the feeling of his heart in his throat. Then, forcing his hand to steadiness, he answers, Madara. Tell me if you need help with your plans. I'm always happy to rid the world of idiots.

Instead of words, he gets a few rapid slashes of a brush, making—

Madara laughs. Laughs like he hasn't since he was a toddler, loud and bright with nothing held back, because—

Because there on his arm, drawn in a steady hand, is a picture of a tiny stick figure with spiky hair strangling another, this one with what is probably meant to be a bowl-cut. Underneath, Tobirama has captioned it, Ten Minutes from Now, Or Whenever Hashirama Opens His Mouth Next.

And, well. Madara honestly hasn't thought much about his soulmate before, but whoever Tobirama is, Madara suspects that they're rather perfectly matched. He grins, and curls his fingers around the handle of his brush. If you need me—

Our signal will be 'meet me by the river', Tobirama answers promptly. Excuse me, he's about to—

The words cut off with a jagged smear of indigo ink, as though someone overenthusiastic just tried to grab the brush out of Tobirama's hand. Madara snorts, already bracing himself to help dispose of the body, and shoulders his gear again.

He's grinning, and for once he can't think of any reason to stop.