7Tags: Time Travel, OP-ish Ichigo, AU, Ichigo/Yoruichi/Soifon, multiple Zanpakutō (Zangetsu [the trench knife], "Shiro"/Hollow Ichigo [the Khyber knife], Kikoo/Sōkyoku [a naginata]) with their shikai forms in the brackets.
Warnings: Language. If you have watched the anime you're good. Lemons? Nope. The M is just for language and gore if I ever get to adding them
Summary: Aizen uses the fused Hōgyoku to send Ichigo far off to the past where he (supposedly) can do no harm to Aizen's plans. Obviously, this does not work as planned.
Notes:
Any other pairings would most likely be minor.
I am treating the Gotei 13 as combined military and police force for SS with Kidō corps as a separate branch specializing in, duh, Kidō. The Onmitsukidō wil be treated as a combined internal security force and special forces/intelligence service. Combat Elite means a frontline combat unit with elite troops, unlike the Stealth Force which in combat would deal with sabotage, reconaissance, and assassinations.
I would be using Japanese/Romaji terms interchangeably with English ones (i.e. start of the chapter Onmitsukidō middle of the chapter Stealth Force).
I'm setting Yamamoto as at least four millennia old, with Unohana being two millennia younger. Shunsui and Ukitake are both around a millennia and a half. The Thousand Year Blood War is Two Millennium Blood War. The Gotei 13 is more or less three millennia old.
Second to the lastly, I will just input parts of incantations for Kidō.
Lastly
Gotei 13 Specializations
1 - Combat Elite
2 - Onmitsukidō
3 - Combat
4 - Medical
5 - Rukongai Protection
6 - Seireitei Protection
7 - Combat
8 - Reserves
9 - Rukongai Protection
10 - Living World Protection
11 - Shock Troops
12 - SRDI (used to be Reserves)
13 - Living World Protection
Extra notes:
"Kami he's big" normal speech
"Fight me" Zanpakutō speech
"I'm talking to myself" mind speech
"Hadō #91: Kurohitsugi" fully incanted Kidō
"Bakudo #4: Hainawa" partially/unincanted Kidō
Dear Diary written stuff
moves such as Getsuga Tenshō, Hirafune, etc. will be normal speech.
On with the story
Prologue - Where am I (Ichigo) Unbetaed
"Getsuga Tenshō!" I shouted as I left the Dangai, aiming the arc of energy at Aizen's unprotected neck