Mayuri soon reached the Human world with Hachigou Nemuri closely behind him and immediately made their way toward the 7th door where people needed to be pulled out first. The Hollows who attacked the 6th door are also in danger, but his priority is his fellow Shinigamis.
On the way here, Mayuri saw how Zaraki had instantly killed his opponent but they immediately revived after. At first, he was disappointed that there is probably no chance of him getting a corpse from Hell to study. Then he also became curious about how they were doing it and intently watched and each time Kiganjou would revive, while also cursing at Zaraki for turning around or covering the camera on his chest.
Nevertheless, Mayuri immediately guessed their intentions when he saw Kaname Tousen not doing anything, 'It's to hold him in place. But it's also safe to assume that these other dead people can revive multiple times.'
Another thing that he noticed was that they had more information than he thought after seeing that Zommari wasn't shocked after seeing Bambietta walk again despite her neck being snapped. And after a few more minutes of observation, Mayaru had a feeling that their enemies didn't actually want to kill Hell's intruders.
Mayuri arrived where the 7th door disappeared and observed it for a bit. But just as he was about to give instructions to the surrounding Shinigamis who were securing the area, his communicator rang. He already gave a reminder to only call him when there's something important that came out so he immediately answered it, [Captain Kurotsuchi, there are unknown people who're approaching the spot where the door closed!]
"Turn on the feed and do not engage. Stay back and observe them." Mayuri immediately instructed and soon enough, he soon received the image of three girls standing in front of the closed door.
'The girls with Sitri Serafall... What are they here for?' Mayuri thought to himself before giving more instructions, "Ask them what they're doing and if they don't feel like answering, immediately take your distance. Do not engage in hostile behavior at all costs and keep the cameras pointed at them at all times."
[Understood!]
However, the Shinigamis didn't have the time to inquire when the girl with golden hair and eyes suddenly took out four paper talismans. The paper talismans floated at the four corners where the door was previously located and after a few gestures from her, a black line emerged in the middle and expanded to a black portal. The door to Hell was forcibly reopened.
Mayuri's eyes went wide open at what he'd just seen, but he didn't let that break his concentration and take in all the information that he could gather right now. He's now regretting not going to the 6th door but there's nothing he could do right now.
As soon as the door opened, the girls jumped in without any hesitation.
The Shinigamis present wanted to approach the now open door but the talisman they left started shaking a few seconds after the girls entered before they shattered into countless pieces. Immediately after, the door closed as if the stick in the middle of it had snapped. The closing created a big enough shockwave to push away the approaching Shinigamis.
[C-Captain, what should we do?]
"Immediately secure our measuring devices and upload their data before something happens to them."
Mayuri wanted to make his way to the 6th door when he was stopped by a subordinate, "C-captain!"
Mayuri turned around and was in for another surprise. In front of the 7th door, a figure is standing quietly without releasing any fluctuation of Reiatsu as if he does not exist.
Wearing a white tuxedo, black pants, a white fedora hat with a black band, black gloves, black shoes, and a pure white shapeless mask that doesn't have any holes, the man with long black hair seems to be staring at the spot where the door opened.
Mayuri didn't immediately talk to him and instead gestured to others to fall back to a safe distance.
The unknown man, on the other hand, put forward his hand towards the space where the door is and a green Magic Circle instantly manifested and its unknown characters rotating mysteriously.
"How are you related to Sitri Serafall?" This is the first question that Mayuri asked.
The strange man didn't stop what he was doing but took some time before he answered, "...Brother-in-law."
Mayuri was not expecting to receive any answer so he was glad that he could continue talking, "What are you trying to do?"
The man took back his hand and the mysterious circle disappeared, "You should have already guessed." The man then took 8 pieces of 1x1 inch black cubes out of nowhere and started tinkering at them.
That tinkering took little time and the man tossed 7 of the 8 cubes to Mayuri's direction.
The one who responded was the small Nemu who ran in front of Mayuri to catch these cubes. Nemu inspected the cubes first before giving them to Mayuri, "This is?"
"Keys." The man briefly answered before tossing the last one that he had in front of him. The black cube became suspended in the air after it reached the exact spot where the door closed. A second later, it released a strange noise before disintegrating into dust. Immediately after a black line appeared and the door reappeared once again, "Gather the Magic Power around the spot where the door appeared and pour them in those. If you can't do it yourself, ask Sera-chan to do it for you."
Without waiting for a reply the man went through the door.
Unlike what the strange girls did, the door the strange man opened remained open, but Mayuri knew better not to follow him and instead just sent some of his surveillance bugs.
Immediately after, Mayuri turned his back to the door and issued additional instructions, "Watch the door and record everything that's happening to it. Aside from that, don't let anyone approach it. Also, ask the Seireitei for more reinforcements in preparation for the personnel pulled out from Hell."
The Shinigamis around him saluted and only eased themselves when Mayuri and Nemu disappeared with a Flash Step.
.
.
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Claire, Kunou, and Tanis warily and nervously entered the door to Hell. Despite that, the three of them were excited because this is their first real battle after their extensive training within the Ouroboros Academy.
As soon as the light returned, they saw a devastated land that was ravaged by intense battle.
The atmosphere around them felt awfully similar to the Underworld and they were taken aback but immediately focused back on searching for their target. A few seconds later, they found their objective but all three of them were bloodied, unmoving, and on the verge of death.
With a quick glance, Claire immediately figured out what was going on and matched it with the information they had, "Poison... Tanis, secure our rescue targets first."
"Understood." Right away, Tanis removed her disguise and her appearance returned to that of a Vouivre. Releasing her Draconic Aura, she immediately caught the attention of their opponents but she ignored them for now and spread out her wings before diving within the poison-filled land to snatch the three Hollows who were conscious, but couldn't move.