Author Note: Welcome to the beginning of what will hopefully be a long series. this story is made up of quick (and not so quick) glances through the eyes of a number of characters to set the scene of my version of this world.
Also I do not own Bleach, but oh how I wish I did..

Chapter Summary
While the Battle rages in Karakura Town opportunistic hollow take advantage of the officers absence and the weakness of the dimensional borders to attack the Seireitei.
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3rd Seat Yasochika Iemura of Squad 4 watched in horror and the sky above the Seireitei cracked open. The Captains and Lieutenants had left to confront Aizen and his armies in the world of the living and Huco Mundo, leaving the 3rd seats in charge of each Squad. They had been told to prepare for the return of the party and be ready to treat casualties, but no one had said anything about an attack here.

"Look sharp," he called to the members of his squad, "assemble into your groups and head out to battle stations."
He proceeded from the barracks to where his group was to assemble. He stopped by each group leader to relay orders, all the while wondering how bad the situation was. Did Hollows appearing here mean that Aizen was on his way, or was this a distraction that was meant to weaken their defenses? He could hear the sounds of battle as other squads engaged the enemies. When he reached his team he addressed them in his calmest voice, trying to mask the worry he felt.
"Listen up, our team is going to support the fighters in the south near 6th Squad barracks, they've begun fighting the enemy there. We are to provide support and medical attention. Do not enter the fight, there are 12 other Squads for combat, leave that to them and focus of what we are meant to do."
"Is this Aizens attack? Did he defeat the Captain?" asked one of the men plainly terrified. Iemura answered as best he could.
"Aizen has not been seen it the battles, it is just normal Hollows." He saw a few of them sag with relief. "Okay standard procedure lets go."
The team moved out across the Seireitei, avoiding the other battles and heading to their destination. As they arrived Iemura noticed that there was a number of strange and extremely powerful reiatsu gathering outside the walls. Some were vaguely familiar but none that he could outright name, and they all seemed to be swirling together. 'A battle then…hummm the Transported Town is in that direction, maybe the fight has come here after all.' But there was no time to worry about that he kept his focus on his immediate problems. There were dozens of Hollows here but none of them were very strong, if a Captain or Lieutenant had been there this fight would be over already, but no such luck. They would just have to hang on until help arrived.
The fighting was fierce, and the casualties were mounting but, nonetheless they were holding their own for now.
From his vantage point he looked across the burning city. Fires were burning in a number of places, and building had been destroyed in large areas around each of the battle sites. Four of the battles looked particularly bad each one contained a Hollow that towered above the others. 'Adjuchas' thought Iemura, 'they are going to be a problem, even Lieutenants can have trouble with them.' He looked over the damaged city, 'there is going to be a lot of work for us to do if we make it out of here alive.'
Just then he heard someone call out, "Look the Captains have returned!" He felt instant relief, with the return of the Captains and warriors this situation had just become more promising.

It also meant that he was no longer in charge.