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The Mechanism of Betrayal

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It feels like dying. He is dying. There’s no other explanation for the terrible pain he feels.

This is death. Shunsui thinks. This is worse than death.

“Gods, Jyushirou . . .” Kyouraku chokes on his own words. His right hand tightens on the hilt of his naked sword, steel dull and broken of will in his hand, just like Kyouraku himself. His left hand shakes as he curls fingers in long white hair, trying desperately to be gentle even though he knows it’s too late for that.

The traitor– monster– is laughing. Kyouraku-taicho drags his eyes away from the sight of his death to see Aizen, standing there and laughing, as if nothing at all is wrong.


Shunsui tries to put anger behind his words, but his voice breaks before he’s even started. He’s too far gone now to hide how it’s affecting him. How it’s killing him. So Kyouraku stops trying.

“You,” he says again, because he has to ask. “What did you do to him?” Aizen has stopped laughing, but he’s smirking at Shunsui.

Gods . . . worse than death. This is so much worse than death.

“Do?” Aizen drawls in that infuriating way that he’s adopted, but Kyouraku is too broken to feel fury. “I didn’t do anything to him.”

Shunsui doesn’t believe him. He won’t. He can’t. The loose fingers resting in pale hair tighten before he can stop them, but there is no reaction. Kyouraku turns away from Aizen and looks death in the face again.

“Please, ‘Shiro.” He’s begging. “Please.” He’s not sure what for. Maybe the truth. Maybe a lie. All Shunsui knows is that he’s broken. Aizen broke him. Because it all comes back to Aizen, doesn’t it?

Or maybe it all comes back to Jyushirou.

I’m dying, Jyushirou. Help me.

But Shunsui knows now that he won’t.


It’s starts fairly simply. Ukitake Jyushirou visits the Academy for a class presentation. The instructor explains who he is, and the students are amazed by his power and age. There is nothing unusual about this. Ukitake does one of these presentations for a first year class every year. He’s used to that sort of thing, and takes pride in inspiring future generations of Shinigami.

One day, three hundred years or so before the betrayal of Aizen Sousuke, a student catches Jyushirou’s eye. He is quiet and unassuming, he reacts as he’s expected to react, and he smiles with a kindness usually unseen in the warriors of Seireitei.

The only other person Ukitake knows who smiles like that is himself. This, of course, makes him interested.


No one really thinks twice when Graduate Aizen Sousuke is accepted without fanfare into the Thirteenth Division. It seems like a good fit to his instructors. Ukitake-taicho and Aizen have the same temperament, they say, and Ukitake-taicho will help Aizen come into his own where other Captains might not understand him.

They have no idea how right they are.


“Here,” Ukitake-taicho says. He places one large hand on Sousuke’s shoulder and reaches around Sousuke’s body with the other to adjust his grip on his sword. “Hold it like this.”

“Why?” Sousuke asks, because he knows this man will explain the truth to him.

“It’s perfect.” Ukitake-taicho says, words ghosting across the back of Sousuke’s neck. Goose-bumps rise along his arms. “It has absolutely no flaws. But it also has no character.”

Ukitake-taicho takes a step, pushing Sousuke’s own leg forward, and begins to guide him through the kata. “Each Shinigami, over the course of their training, adjusts their styles and techniques to fit themselves, to compliment themselves and their unique Zanpakutos.” Ukitake-taicho pauses them again and makes another adjustment in Sousuke’s form. “This has power, of course. But one has more power in anonymity. Being unique means you stand out.” Another pause, another subtle change. Then Sousuke is being guided again. “Being perfect in your form also means you are seen as less than those who are unique. If thought through logically, this doesn’t make much sense, but perceptions rarely make any sense, and are always stronger. Play to those. You’ll be underestimated.”

Ukitake-taicho stops again, but this time he pulls away and walks around Sousuke to stand in front of him. Sousuke feels suddenly chilled and bereft, which intrigues him. He should have Ukitake-taicho teach him how to do that as well.

Ukitake-taicho looks Sousuke in the eye.

“This is the most important thing I will ever teach you. Always be underestimated. It is key. It’s your strength.”

“Yes, Ukitake-taicho. I understand.”


There are truths about Aizen Sousuke that few people understand.

Ichimaru Gin understands some. Tousen Kaname understands not at all. There is only one who understands Sousuke as he truly is, and that is Ukitake Jyushirou.

The reason for this is simple. Ukitake Jyushirou taught Aizen those truths. Ukitake taught Aizen everything.


“Kyouraku,” Jyushirou says, the single word bringing all of Shunsui's attention back around to him. He's suddenly trying to remember when they stopped calling each other by their given names. It seems more important now than it did when he'd first noticed it.

“Kyouraku,” Ukitake says again, and brings a gentle hand up to the one Shunsui has fisted in his hair, untangling it. Kyouraku lets him. When he's finished, Jyushirou doesn't let go of his hand. “I am under no influence here. This is what I want. You know as well as I that Seireitei can not go on like this. Something must be done. And if that something is what Sousuke is proposing, then I will support him in his endeavor. Think, Shunsui,” Jyushirou urges with a squeeze to their joined hands, but it is the use of his name that really brings Shunsui's attention into focus. “Think about all the discussions we've had about the problems plaguing Seireitei because Yamamoto-sensei refuses to adapt with the times, because Central Fourty-Six follows his lead, because there is nobody but Yamamoto-sensei to say otherwise. This is the solution we've always wanted.”

This?” Kyouraku-taicho replies in disbelief. “Do you know what that monster-”

“That's my student you're talking about, Shunsui.”

“-did to Hinamori-fukutaicho and Hitsuguya-taicho?”

“Of course,” Jyushirou says mildly. “I got the same message from Kotetsu-fukutaicho that everyone else did.”

“How can you even speak like that about it?”

“It's simple,” Jyushirou tells him. “In this instance, the end justifies the means. Sousuke needed more time to find the alternate extraction method, as I was fairly certain the Sokyoku would damage the Hogyouku during the execution.”

“Is that why you were so set upon this course of action?” Shunsui demands. “To protect that trinket?”

“Of course not. If there was a safer and less damaging extraction method, as there always is with Urahara-san, then aren't I required to do everything in my power to prevent the needless death of my subordinate? And you, Shunsui, you were amazing. I couldn't have saved her without you.”

“What are you talking about?” Kyouraku finally manages, head spinning and confused. Ukitake seems just like the same friend he's always had, but how had it gone this far without him noticing?

“I'm saying I want you to come with me, Kyouraku. Follow where I lead. Believe me when I say that this is the best way. The same as I've always asked.”

“Kyouraku-taicho,” Yoruichi snaps from where she and Soifon-taicho have Aizen pinned, her voice bringing him back into the present situation and all that it entails.

Shunsui doesn't look away from his best friend's eyes. The eyes that seem to be simultaneously trying to kill him with their betrayal and to save him from it.

Kyouraku-taicho knows that there is no going back from this. Either way the Gotei 13 have lost five Captains today. It is a masterfully genius stroke. Shunsui wishes he could believe that Aizen was behind it.

Kyouraku breathes out, “No.” He shatters inside as he says it. But his squad and his city and his people have always come first. Before now, Ukitake had given him that. But that doesn't matter any more.

“I see. Alright, my friend, it's alright.” Jyushirou releases Shunsui's hand and pats him on the shoulder. He glances past Shunsui and says, “Ise-fukutaicho, take care of him for me, will you?” And Shunsui takes a moment, just a second, to glance over his shoulder and check that his Lieutenant isn't in any danger. The next thing he knows, he's hurtling across the ground and his chest feels like it's exploded inwards.

“Ukitake!” Yamamoto roars, and he knows how strong and dangerous Jyushirou is, but using Sho to cave in the left side of his chest without even an enchantment? What would the effects of a Sokatsui or a Raikoho be, in that case?

“Looks like it's time,” Shunsui dimly hears Aizen say, even as Nanao slides to her knees next to where he's come to a stop.

“Soifon, get away from him!” He hears Yoruichi scream, and then the strange distinctive hum of a Garganta opening.

“Stay with me, Captain,” Nanao is saying.

“You have joined with the Menos and the Hollow. Why?” Yama-jii asks.

“Sousuke will explain it better than I,” Ukitake tells their sensei.

Shunsui wonders when his friend stopped calling him by his name. It's hard to pinpoint. More than two hundred years, now.

“Please, Captain, stay with me.”

Shunsui opens his mouth to speak, coughs up blood instead. It's fitting, he thinks. But what he has to say to Nanao is more important.

“Take care of the Division, Nanao-chan,” he gasps out.

“No, no, Captain, Unohana-taicho is right here, she'll take care of you.”

“Tell her- not to bother.” Shunsui manages. “I'm . . . already dead.”

Kyouraku Shunsui closes his eyes and remembers. The first time in so long that Jyushirou had called out 'Kyouraku' to get his attention instead of 'Shunsui' was two-hundred and eighty-two years ago now. Aizen Sousuke had been his subordinate and personal student for less than ten years at the time. He hadn't yet achieved Shikai.

There had never been any blame to place at Aizen's feet. Ukitake Jyushirou had been the architect of Shunsui's death. Kyouraku hopes, selfishly, just a little, that Ukitake wins. Because then, maybe, this betrayal will have been worth it. Then Shunsui's death will have meaning. Then his friend will live.

It is Shunsui's last thought before the darkness swallows him up.