Their deaths were celebrated as an afterlife holiday. It marked the end of the war, it marked the end of three traitors thought nigh invincible. It ended with a God impaled on an obsidian sword's razor edge, staring impassively into wide, golden-black eyes hidden behind a half-broken mask.
It ended with one fell blow that felled an entire revolution.
Gin Ichimaru and Kaname Tosen are not slain. They have merely been taken prisoner, after the death of their leader, Sosuke Aizen. Tosen is morbidly silent. Gin is cracking grim jokes. They wait for their looming execution dates. Their loved ones, their friends, the few they still have, are not at their sides. And really, they understand this. Gin wouldn't want Rangiku to be put through hell just to kiss him goodbye, if she'll even look at him after all he's done. So he's content with his death. Tosen is an enigma; it's unknown if he's content with what he's done, how his glorious, bloody path to a self-defined justice ended.
Everyone rejoices. Everyone parties for one day, three days, a solid week of merriment. Everyone, except one man. The Hero of the Winter War has no solace. No one can comprehend this. Why not? He killed Aizen in a duel to the death. He won this war for them. Why doesn't he enjoy it like they do?
"Enjoy yourself!" Renji claps him on the back, bellowing good-naturedly. "You killed that fucker for us, and you're not even enjoying it!"
Ichigo grins, grimly, but offers no words as Renji drifts off to talk with someone else.
"You're pretty fuckin' grim," Ikkaku jabs his glass of sake in Ichigo's direction, almost splashing him with the alcohol, "For someone that won a goddamn war!"
The substitute shinigami sighs under his breath, lays his head down on his arms exhaustedly and rests at the table while Ikkaku and Yumichika regale the tables with tales of the War, of the Espada they slew, of the killing they did.
"Why so serious?" Rukia asks, not unworried. "You look so tortured. Is something wrong?"
He smiles a rictus at her, until Byakuya beckons her over to speak with and she leaves him be.
Ichigo is the only one who doesn't enjoy his victory. But then again, he's the only one that hears the voice echoing in the back of his consciousness. A smug, smooth croon that entails nothing but pure, total victory. He's the only one that lays awake at night, listening to a dead man whisper horrid secrets to him, tales of what the world will be like after the revolution is through. Kurosaki is the only one that closes his eyes and sees a smug, not altogether displeased smile behind his eyelids, a pair of smoldering brown eyes tinted with evil. And the voice. He hears the man's voice every moment of the day, until he's sure he'll go absolutely mad. His hollow has fallen silent, already engulfed by the invader's presence. Zangetsu is gone. There is only the sweet whisperings of Aizen in his mind.
'How did you do it?' Ichigo had asked him, the night that his voice appeared. It slid out of nothingness, a slow hum that eventually formed words, sentences, sweet little lies meant to calm him, make him hand his sanity over on a silver platter. The night after Aizen's death, the night that his sleep is thick and smothering and sticky, he dreams of the voice that he has wanted to convince himself is a lie, is his imagination. It's not, and he knows damn well that it's not. He dreams of standing in his shinigami uniform, standing opposite another form. A man that is dead. A man that shouldn't be inside his soul, but is, a man that turns to look at him with a sweet smile totally unbefitting a tyrannical overlord that made a desperate grab for the stars, for Heaven's throne.
"Mr. Kurosaki," Aizen says his surname pleasantly, tossing the limp body of Ichigo's own negative copy, his hollow's physical manifestation, at his feet. The white Zangetsu is in the killer's hands, where Kyoka Suigetsu should be, and ruby blood drips from the tip of the blade onto the windows beneath them. "It's very nice to see you again."
Ichigo attacks. Aizen is quick, too quick; he knows Ichigo's movements before he even makes them, and the two move seamlessly in their battle. There is no submission on the invader's part; however he came here, he's not going to submit to Ichigo's will, and lets this be known loud and clear. The fight ends in a draw, Ichigo out of breath, Aizen still smiling as pleasantly as can be. Ichigo notices for the first time that his own thin black Tensa Zangetsu is matched by Aizen's white mirror image; as soon as he entered Bankai, so did Aizen. This confuses him greatly. Then the questioning begins, Ichigo's hostile demands of an explanation of why a man he killed is within his soul, and Aizen answers in a nonthreatening, overtly pleasant manner.
"You should be very careful of whom you kill, Mr. Kurosaki," He narrates, as Ichigo stares at his hollow's unmoving body. "There is much unknown about the powers of some."
Ichigo pulls his Vizard mask, and Aizen pulls his own. Kurosaki halts at the sight; Aizen allows his to dissipate, like mist. "You've little knowledge about the possibilities of Vizard powers. Neither you nor Shinji are completely aware of what a Vizard can do, with the correct...alterations." He chuckles, sits down at the edge of the sideways building, examining the expanse of Ichigo's inner world. Ichigo does not see the thick cloud of fog at the very edge of the horizon.
Ichigo is wrenched from his inner world, and he almost thinks it's at Aizen's whim. This terrifies him beyond words, as he wakes up covered in a sheen of sweat, gasping for breath, his heart racing. And, despite his few seconds of fervent wishing, hoping that it was just a dream, a calm voice chides in the back of his mind, fatherly and smug.
"Ah ah ah, Mr. Kurosaki. Did you think I was a figment of your troubled teenage imagination? I'm not. You took my life, and you took my body; it's only fair that I have a new one, and it's only justice that you share yours."
Ever since this grim revelation, of his possession by a very distantly angry spirit seeking what, revenge? Ever since this, Ichigo has been grim, tortured; Aizen tells him things that he should never want to hear, things he never, ever needs to hear. Orihime was rescued after Aizen's death, the fall of Las Noches, but she came back...different. Shaky, nervous; tortured. She won't say what's been done to her, but everyone's gut instinct told them that it was suitably horrible, and Ichigo would have gladly left it alone. He would rather have never known, and wouldn't have, until Aizen whispers dark secrets to him; calmly croons intimate details of tortures, horrors nameless by their sheer depravity. It drives him to the brink of insanity to hear these things every moment of his day. But he can't tell anyone, not the shinigami at least; they'll either call it shellshock, belated trauma caused by the war, a guilt complex he has for all the blood on his hands, or they'll do what Ichigo fears worse, and knows that it would happen; they'll believe him. And then they'll have him executed for the safety of the Seireitei and Soul Society in general.
The Vizard? They're an unattached third party; there's no way to know whether they'd believe him or slaughter him on the spot.
Urahara? Ichigo isn't sure about Urahara. He wants to reach out to the man; to ask for help, guidance, as the ex-shinigami has offered so many times before, but he can't bring himself to do it. There is danger in exposing anyone else to Aizen, to a possibility of jumping from Kurosaki himself to anyone he pleases, and Ichigo won't expose his friends to danger. He smothers Aizen's influence all within himself, and the tormented rictus of a smile is the only hint that something is terribly, terribly wrong.
And so that's where Ichigo lies, a martyr for the cause; a sacrificial lamb that nobody knows about, or notices, in their post-war revelry. They all chant of Aizen's fall, unaware that the phantom of their nemesis lies in their greatest hero, patiently biding his time.
The time passes slowly for Ichigo. Aizen has replaced both Zangetsu and his inner hollow; the Lord of Las Noches himself is the new hollow in Ichigo's soul. The minutes tick by in either thick silence, pure and thick and strangling, or they fly by through mindless mental chatter with Aizen, usually dark and insidious chats that end in Ichigo tormented and Aizen pleased. The topics are always depraved. No matter how hard Ichigo tries to ignore the calm voice in the back of his mind, it always penetrates his thoughts, explaining in great detail of some torture Orihime endured, of how many times she screamed for her Kurosaki-kun, of how desperately she wanted him to save her. And it never, never fails for Aizen to add one little footnote to all his Hannibal Lectures:
"And it's quite a shame that you were never there, hm?" He'll add, in one form or another, cheerily, and Ichigo screams through his thoughts for the man to silence himself, to shut up. He'll chide Ichigo then, like a teacher scolding a naughty schoolboy. "Language, Kurosaki. It's no use swearing at your other half, now is it?"
That's the problem. Ichigo can never be sure if Aizen's really there, or if he's just going insane. There's no way to tell. He's very sure that Aizen's real, that his tormentor is not himself, because why would he torture himself like this? No, he believes that it is not him, that Aizen is definitely real.
His rictus smile becomes more and more strained as time goes on. And he does smile like that, more often than not when someone is asking if he's alright. He can't say that he's fine. He isn't, he's far from fine. But he never says this aloud, never tells Rukia, Orihime (never Orihime), Renji, Urahara, anyone. "They won't understand, Kurosaki," Aizen explains, and after enough time of hearing it, Ichigo believes it. They wouldn't understand, they just wouldn't. "Only you and I understand," Aizen explains. Ichigo begins to believe that too, after hearing it enough. Only Aizen understands the torture Aizen does to him. Of course Aizen's the only one that understands. He's the only other one that knows about it.
Gin Ichimaru and Kaname Tosen are executed without incident. Aizen is calm about this, doesn't even comment when he sees his fox-faced protege, smiling a rictus identical to the one Ichigo's been wearing as of late, die as Izuru Kira, in lieu of the as-of-yet unelected Third Captain, takes his life with Wabisuke. His head rolls. The Third Lieutenant's shihakusho will need to be washed and washed again, to remove the spray of traitor blood arcing in a geyser across his front, due to bad positioning or maybe through a last maliceful act by Ichimaru. Matsumoto does not attend, and is not required to by her Captain, who remains grim as he watches the former Captain's death. Shuuhei Hisagi takes his ex-Captain's life as well, though he himself has already taken the mantle of Ninth Company Captain. Tosen is executed as silently as expected; he makes no last testament, while Ichimaru glances at the gathered shinigami and grins, managing a "Be seein' ya" before his death.
Orihime tries to become closer to Ichigo, who gently pushes her away. Not because he doesn't want her, and not because he enjoys the look of hurt and rejection in her eyes even as she smiles at him and mouths, "I understand". It's to protect her, he insists to himself, and to Aizen, who is always ready to comment on his heartlessness at a moment's notice. Rukia grows distant, can't understand him anymore; she and Renji become closer instead, and Ichigo fully supports her choice. Nobody should be near him. He needs to isolate this disease, this affliction known as Sosuke Aizen; it's dangerous enough as he lives with his family. He's not sure of what he's afraid will happen, but feels that something horrific will happen if he's not of the utmost care. Yuzu and Karin don't get him anymore, and though he can't help it, even though they do try to connect with him still, he pushes them away and remains in his room for a good portion of his day. His father's friendly assassination attempts are now dodged, blocked by pure nervous instinct. After enough time, Isshin Kurosaki stops the attacks, leaves Ichigo be, though he's always got this worried expression on his face when he looks at his son, who by now is pale, dark circles under his eyes, skinny; Ichigo looks sick, and can't help it.
He confronts Aizen more than once. Tries to drive him out. Tries to subjugate him, like he did with his hollow. But Aizen will not be banished; though they spar with one another, a desperate attempt at gaining peace on Ichigo's end and an amusing game on Aizen's part, their swords never meet neither flesh nor cloth, as the two of them always seem to move in sync with one another and never land a blow.
At school, Ichigo becomes sullen, withdrawn; his friends slowly move away from him, leave him be. He's not the same, has no spark in him anymore; just fear, just self-control, just restraint and terror. Tatsuki spends time trying to unearth what's wrong, to figure out what put the tormented look in his eyes, to try and help him as his dulled eyes practically beg her to, but she can't, and eventually gives up on him in order to comfort Orihime instead. Orihime is responding better than Ichigo is to whatever torment she's been inflicted with; Ichigo knows what, he knows too well, and he can barely look at Orihime's face without seeing it twisted in agony, can just barely hear her voice without imagining her screaming his name, agony in her very tone. He can't bear her, or the guilt she brings him.
And so he distances himself from everyone. Aizen is his only companion now. And the ex-shinigami is happy to deliver his company.
Soul Society is calm, peaceful once again.
Ichigo Kurosaki is nearing the breaking point.
His inner world is covered in fog now, thick and choking, and Aizen is his only companion. Either a malicious spirit driving him closer and closer, methodically, towards insanity, or a figment of his own mad imaginings, proving he's already there. He has isolated himself completely, driving away all his former comrades and friends. It's better that way, he tells himself. It's better like this. It's better this way, Aizen insists. It's better with just you and I.
Ichigo notices, after a span of time with Aizen in his consciousness, that his hollow mask has changed. It's not his mask anymore; it's Aizen's, a noble thing with a bone crown upon the head. He's so tired nowadays. So exhausted. He just wants to sleep.
"Ichigo," Aizen offers one day, as Ichigo sits on the edge of his bed, his head in his hands, "Would you like it all to go away?"
Aizen can sense the dull flicker of alert at his words, almost-but-not-quite alarm. "What?" Ichigo asks, aloud. When he's alone, he doesn't even bother just thinking anymore.
"I can offer you a respite. The sleep you haven't had in ages. I can give you your rest." The temptation is overwhelming, as Ichigo drags himself to his bathroom, stares into his mirror. The circles under his eyes are dark, deep; the brown eyes once filled with the spark of life are now dull, empty. His skin is paper pale; he looks sick, underfed. He's desperate, far past desperate. Aizen's voice falls to a soothing croon, warm and inviting and without a drop of malice or ill intent. "Just let me have you, and you can have your rest."
How many years has it been? Five, six? After the Winter War, Ichigo moved to Tokyo, and now, in this dark little apartment, all alone from any sort of salvation, beyond the help of a friend to bring him back from the brink, Ichigo Kurosaki closes his tired eyes, and after a moment, they open as a calm, darkly confident pair. His posture, slumped in constant defeat, straightens instantly, as the man inspects his body, appraising it. Has he given in to Aizen, or has he just snapped? The question is unbidden; only Ichigo Kurosaki knows that answer, and the answer is communicated silently to the empty room.
Ichigo Kurosaki is in good spirits again. He blames it on a slump, trauma after the war. No one blames him for it. Relationships are formed again; old, tattered bonds are reformed, strengthened. Kurosaki is back to his old self; confident, and soon enough, Orihime Inoue is back at his side, cheery and kind. The two can be seen together, and it's obviously more than friendship, though you'd never get as such out of either of them. Matsumoto and Kira seem to be together quite a bit as well. Renji and Rukia have made it official. Kyoraku and Nanao are drinking together on occasion. Komamura and Hisagi are good friends after the War. Love is in the air, and something is in the water.
But there are things you'll never see, unless you're paying minute attention to every person you run across in Seireitei.
Things like the dark, calm and thoughtful expression that crosses Ichigo Kurosaki's countenance now and then.
Things like the terrible ear-to-ear smile that flashes across Izuru Kira's face, like lightning, when he looks at Rangiku and when he thinks nobody sees him.
Things like how Hisagi seems to stare off into nothingness, almost as if in a daze over what he sees.
Things like how Ichigo, after accepting Captaincy for Fifth Company, Izuru, a Captain of Third after the newest one died under mysterious circumstances, and Hisagi get together sometimes, all alone.
Then again, things like this happen all the time. And it's your choice if you want to be paranoid about them or not, isn't it?