The bulk of the training that Ichigo and Rukia have been going through has either been on or near the Sokyoku hill. This is mainly to keep their reishi away from anyone much weaker than them from being exposed or even corrupted by their hollow like reishi. With the Kido Corps training grounds being close by it wasn't a stretch from their usual spots to train there as well. While Ichigo isn't as adept as his allies at sensing reishi, he knew Rukia's almost as well as he knew his own. He felt her leave to go train with Hiyori shortly after he was instructed by Yamamoto to repeat the kido spell 10,000 times. However he was a very fast learner and by the past hour of Rukia and Hiyori's sparring match he had already completed 1800 perfect casts according to Tessai. He only restarted once around the 150 mark the first time but now he's gotten it down to the point he can perform it by flicking a finger. However as he continues to snipe the target with the concussive blast of the first Kido, something feels amiss. After he reached the 2,000 mark he drops his hands and turns to Tessai to address what he's been feeling.
"Hey Tessai?" Ichigo asks, his usual nonchalant tone slightly exasperated due to the constant repetition.
"You are on 2,012 casts Kurosaki." Tessai responds, assuming that he was going to ask what number he is on.
"I wasn't gonna ask that, I was going to ask if you could have someone check on Rukia. Something feels... off." He explains, prompting the tan skinned buff man to peer over his tiny glasses at his student. "Her reishi feels like it's getting weaker."
"Third seat Hiyori had mentioned that they were going to train until her Reishi was depleted so that she may have her inner battle with the hollow." Tessai responds, though the look of concern on Ichigo's face does convince him to at least humor his request. "If it will get you back to your training then I will have someone go check on her."
"I'll grab Shinji and Kensei, knowing Hiyori she's probably going to do something stupid." Lisa sighs, annoyed that the young soul reaper is distracting her from her manga. "Hiyori's reishi feels like she's using her hollow powers, so she's definitely doing something stupid."
"Oh I think they're gonna have fun! I'm gonna go too!" Mashiro declares before rolling backwards into a handstand and pushing herself off the ground and vanishing in a burst of reishi.
"Well now that that is sorted Kurosaki, please resume casting the kido spell." Tessai asks, with the concern lifted from his shoulders, Ichigo turns back to face the target set up for him on the far side of the courtyard. He raises his hand and channels as little reiatsu as possible to fire the spell and does so. "2,013 and counting. Less than 8,000 to go. At this rate you'll be done in time for dinner this evening."
Hardly a second after the words leave his mouth the target explodes violently from an overcharged cast of the spell. "Maybe not. Starting back at one." Tessai dodges a cast aimed at him before clicking the counter. "Two." He says with a slight smirk on his face. However just as Ichigo goes to cast it again, the Rukia's energy shifts increasing massively and turning dark, the tell tale signs of hollowfication. His eyes widen in shock, feeling his girlfriend's spirit energy hollowfy and before Tessai could tell him not to go after her, he takes off. Grabbing Zangetsu by the massive wrap around its handle, sprinting as fast as he can to the training ground.
Halfway across the Seireitei in the squad five barracks, Shinji and Kensei are having a conversation on what to expect with Ichigo's hollow powers. They have been told of how strong the hollow version of Rukia is and considering the fact that Ichigo is at captain level, his inner hollow is bound to be nearly as strong as captain Kyoraku if not stronger. "You feel that?" Shinji asks, feeling the sudden shift in reiatsu coming from under the sokyoku hill. "I think Miss Rukia's hollow just woke up." He says, prompting Kensei to arch an eyebrow and then feel out the darkened reishi that now permeates the air. "Yeah, and if it's this dense this far away, Hiyori is in deep shit." Kensei responds as both captains stand. "Captain!" Lisa shouts as the rice paper door slides open. "We need to go now, Rukia has hollowfied we need to get there before she kills Hiyori. I've already contacted Hacchi and he's meeting us there." Lisa warns, though the captains don't answer instead they act. The four soul reapers flash step as fast as they can to get to the training ground.

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The Hollow Queen
FanfictionAizen had created many hollows with his experiments on Hollowfication, however his greatest masterpiece would come in the form of Fishbone D. This hollow could force those that it had bitten to manifest an inner hollow. This same hollow was the one...