Nakago kept Tomo's clam shell, which struck me as odd.  This takes place right before he opens it and sees the miko's world.  Enjoy!
 

    Nakago cradled the clam shell in his hand idly, running his fingers along the smooth surface.  A tiny remainder of Tomo's chi lingered in the shell,  like an afterthought of the shell's previous owner.  The weak energy could barely be felt, like a ghost half-caught in the next life.  It was a warm pulse to Nakago's finely tuned senses, a pale echo of the one who had placed his energy there in the first place.  And yet, now it was all that remained of Ruo Chuin.
    The body itself was already cold and empty by the time they found it.  The scouts had immediately brought it back to the main camp, the ryuseisui still strung through it.  Nakago had given the soldiers the gruesome task of pulling the ryuseisui from the body,  then he himself inspected it.  That was when he found the unbroken shell, with Tomo's energy still trapped inside.  They'd burned the body, but Nakago had decided to keep the shell.
    Tomo was dead.  That meant that Soi was the only one left.  Something in Nakago wanted to feel hurt, but he fought that urge back.  Tomo's death had been necessary anyway.  Nakago eventually would have had to eliminate him.  Unlike Soi,  Tomo could have become dangerous.  He might had decided to go after his own wishes.  Nakago knew what Soi wanted, and he knew she would be satisfied with or at least accept whatever he gave her.  Tomo, however... what Tomo wanted...

    The palace was always cold and dreary, but at night a new layer of menace shrouded it.  From the hall of the Emperor's quarters,  where the occasional harem girl's cry or Emperor's grunt pierced the air, to the bunks of the soldiers where half-whispered conversations were punctuated with harsh, mirthless laughter... the air was thick and clammy.
    Nakago had encountered Tomo in the main hall of the palace.  Tomo had been watching the night sky through the window,  observing the dark clouds that gathered over Kutou to blot out the moon and stars.  He didn't turn until Nakago was stranging right beside him.  The broken light from the window reflecting on his facepaint gave him and eerie, dangerous look.  He smirked slightly at Nakago.
    "You're up late."  Tomo noted softly.  "What brings you out into these dreary halls?"
    "You're out late as well."  Nakago said.  "Why are you here?"
    Rather than answer, Tomo's smirk softened slightly, and he turned back to the window.  "It's going to rain."
    "So?"
    "... I dislike the rain."  An odd look crossed over Tomo's face, but it quickly smoothed back out again.  He turned back to Nakago and smirked.  "Do you like it?"
    "It's the rain.  I neither like nor dislike it."  Nakago answered evenly.  Tomo gave a slow nod.
    "What do you like, then?" Tomo asked. "You must have something that you like." Nakago remained silent, until Tomo prompted, "Do you like Soi?"
    "Soi is one of Seiryuu's seishi.  She's necessary for the summoning." Nakago answered.  Tomo smiled.
    "Aren't we all.  But you share your bed with her.  Will all of Seiryuu's seishi share that?"
    Nakago glared dangerously at Tomo for that, but Tomo remained calm.
    "So that's a present just for her, isn't it? I'll never know why you chose her."  Tomo continued smoothly.  "For her reassurance, maybe? Not for your own, certainly."
    "My reasons are my own."  Nakago answered tersely.  Tomo's face lightened slightly, and the smile on his face became almost gentle, maybe even affectionate.
    "Don't worry.  It's our secret.  You don't have to be afraid of me."  Tomo turned back to the window.  "We have more in common than you imagine." Nakago didn't answer.  Tomo commented quietly,  "You've never asked me why I came with you."
    "Because you're a Seiryuu seishi."  Nakago answered.  Tomo's smile twisted slightly.
    "You certainly fake stupidity well.  No wonder you rose so quickly in the ranks of the army."  Tomo shook his head slightly.  "Do you honestly believe that I came here for the sake of Kutou, or because of a duty to that brat, Seiryuu no Miko?"
    Nakago remained silent.
    "Why did Amiboshi and Suboshi agree to come and stay here?" Tomo asked.
    "Because they prefer living in a palace to living on the streets."  Nakago answered dryly.
    "No.... No, that's not exactly right."  Tomo shook his head.  "It's because they love each other strongly.  Because Amiboshi thinks it's best for Suboshi if they are here, and Suboshi thinks it's best for Amiboshi.  Neither of them are worried about themselves.  They're just here for the benefit of each other."
    "That doesn't answer the question of why you are here."  Nakago said.  Tomo looked over at him slowly.  A strange smile crept over his face.
    "Guess."
    "What?"
    "I want you to guess why I'm here."  Tomo answered.  He walked past Nakago,  down the hall.  Nakago turned to watch him go.  Outside, the sound of rain hitting tile echoed through the courtyard.

    Nakago had always thought that the clam shells Tomo used were rather ugly, brown and dull.  In the candlelight of his tent, though, he could see a strange sort of shine to the clam shell.  The chi inside still pulsed loyally, the spell waiting for its master to come and make use of it.  Casually, Nakago flipped the shell open.