The dim light makes it nearly impossible to see clearly. The room is quiet, save for the occasional growl as Tobirama squints in the dark, too far into his work to retrieve more candles.
The candles he did light warm his bare back as he leans over, brush in hand, thighs and eyes straining as he traces its path with his eyes. His brush glides behind, trailing black ink in thick, straight lines just under Mito's collar bones.
It dips lower, barely kissing her sternum. When it moves lower, towards her rib cage, a muscle twitches in her cheek, barely perceptible. A sign.
Tobirama considers his next move. The heart is too volatile - and too valuable - to make it an anchor point. The brush moves further down, to her stomach, where he pauses again. His research has all but confirmed that his chakra will not center properly there.
Further down then. He reaches the plateau between her hip bones, an abrupt end for his work. Her center is where he must end, though his anchor will need to be separate from that.
He works under his own shadow now, Mito's torso charcoal grey, only shades lighter than the dark lines he traces over her skin. Tobirama growls in frustration and, with his brush still pressed flush against her skin, hefts one soft thigh over his shoulder, his chin lined with her groin.
"There," he murmurs, as the candlelight spills over her bare flesh.
His left hand, the one not holding the brush, runs up the outside to her thigh and strokes her hip, his quick mind cataloguing each ridge of taut muscle and valley of smooth skin.
"Certainly not," Mito says, her voice flat and critical, when his brush lingers too long in that area.
"Certainly not," he agrees, somewhat distant, as his fingers ghost over her exposed hip bone. He cups it lightly, stroking one thumb over the curve of it.
It is an absent-minded gesture, more so from habit than anything else. Still, it causes a shudder to run through Mito's body.
Taking her indirect suggestion, Tobirama loops the next line of his seal over her other hip, skirting her lower stomach entirely.
Like a simmering pot, a series of black lines bubble up over her belly as the seal there awakens. The beast trapped within her purrs lightly, signaling neither approval nor displeasure. Its mere acknowledgment is a threat.
It is familiar enough with Tobirama's own chakra signature by now, though it seldom pays him any notice. Never, however, has Tobirama trodden so closely to its domain.
"Ah?" He looks up to see Mito's forehead somewhat creased, her eyes closed.
Her brow smoothes, and she gives him an imperious wave. "Do continue."
His brush circles the kyubey's seal, sitting subordinate to it, in a way that should provide the beast with little, if no, ammunition to fight its constraints.
"It is somewhat crooked," Mito notes lightly. "It will hold, but the balance of weight around the muscles is not quite accurate."
Her voice is academic, though the neutrality of it makes the criticism harder to deflect.
Tobirama's cheeks grow warm. He feels like a young boy once more, subject to Mito's appraising eye.
"Allow me to work," he says simply. "And perhaps I will surprise you."
The arch of Mito's brow is perhaps more coy than it ought to be, but when she does not respond, he assumes she is content to let him continue. Lifting his brush once more, Tobirama quickly dips it into his pot of ink and returns to brush small, featherlike marks around the curve of his seal, as if they were radiating from it.
He repeats this process on the inside of the seal, making each mark with measured strokes of his brush. "Push and pull," he says, to her unspoken question. "The circle need not be perfect, as it will be moderated this way."
Mito wrinkles her nose but is otherwise quiet. This is the only way for him to know that he has not wholly offended her traditionalist tendencies.
He does not bother to conceal his smirk as he places his brush and ink pot aside, leaving only him and Mito lying bare to him, her gossamer robe draped open and concealing nothing.
Her red hair spills around her, so deeply crimson that it takes on a purple hue in the low light. The furthest strands of it glow in the candle light, liberated from the tight confinement Mito keeps them in during the day. Now loose, her hair spreads down past her hips, pooling around them both in gentle waves.
It is only his work that keeps him from taking advantage of the opportunity to run his fingers through it.
Once more, he feels like a much younger man, stealing glances at his brother's strange bride for the minute facial expressions that would hint toward her pleasure or displeasure. If only he'd known then that gaining her respect would come with the impossible burden of maintaining it.
Candlelight flickers as he gathers chakra to the tips of his fingers. Activation is the easiest part of forming a seal, and yet, in times like these, it can be the moment he dreads the most, when either he will succeed or spend the remainder of this night at work in his study, seeking out the cause of his failure.
With his keen sensing, he can feel the beast within Mito shift, curious, as he lowers his hand. It has been a part of her for so long that he imagines it is indifferent to most things, given over to its own helplessness between the fine weaves of Mito's seal work.
And a seal like this, while resting very close to the place where it has made its home, should be of very little concern to him.
With a measured exhale, Tobirama releases the pooled chakra into Mito's abdomen. The black marks of his seal glow a bright sky blue before solidifying. She sucks in a breath before setting her hand on top of his, fingers pressing into him as the seal sinks into her skin.
He monitors it, eyes steady as he tries to track the flow of chakra. For now, at least, the seal at least is functional, though whether it will be effective is another matter. Later, he will look to perform a full diagnostic, testing the integrity of the seal with several bursts of chakra to ensure it will maintain its shape.
He has no reason to believe this first attempt will not be successful, but if it is not, it is something he wants to be sure of as soon as possible.
When he looks up, her eyes are closed and her brow tight, though in true Mito fashion, she's otherwise stoically silent. When she opens her eyes, they have a glassy, dazed sort of expression. He places a kiss to her jaw and draws his hand up her side, careful not to touch the area he has just marked.
"Are you tender?" he asks.
After a moment of consideration, Mito shakes her head. "Not too much so."
"Too much for what, exactly?" he asks, somewhat coy.
Mito glares at him as she rises on her elbows. Her skin is glassy, shoulders bright with sweat in the warm light, the space between her breasts flushed.
Part of his observation is strictly scientific curiosity, though he could not deny that the view is a pleasing one as well. With her slightly heavy breathing and tousled hair, her open robe and glowing skin, Mito looks more like a well-loved concubine than a test subject.
Perhaps she could be a little of both.
He tips back on the balls of his feet as she rises, though is quickly tugged forwards Mito's lightning-fast hands digging into the fur around his shoulders. Her breathing is heavier, obsidian eyes drunken.
"The seal is rather unstable right now," he says, as a blush climbs to his cheeks. "We ought to let it settle first rather than risk… an accident."
Mito's lips, thin and knife sharp, curl into a mischievous smile. "Do you intend to wait that long, my love?"
"A month, at least," he offers. He traces the outline of the seal with the tip of his finger, dipping with the rise and fall of Mito's stomach as she breathes.
It will fade soon, becoming secret, like much of what they do.
Would Hashirama be upset? It's impossible to say. He'd been good to Mito - and she him - but it had not been the passion of his life. She had not been the passion of his life.
Love was seldom a factor in such marriages, though it was not uncommon that the attachment that followed was as strong as the real thing.
As for what it is that they do… Tobirama can excuse it to himself, but never would he seek to legitimize it.
As if to put a capstone on their experiment, he lays one kiss to her shoulder, then her mouth. "A month, then, and we will revisit."