The first thing Kisuke did is to don his Hollow mask and used Descorrer to split open the space. He's already expecting it when he entered this space, but he couldn't help clicking his tongue when he confirmed the result, 'Tch... 5 minutes to open. This space is a lot tighter than those set by the Perseus Clan...'
Kisuke could focus on splitting the space and only do it for 1 minute, but he would have to dedicate all of his attention to it and that's not a very good move with enemies aiming for your neck. He could also devise a magic circle that could bypass the restrictions in this space, but it has the same problem as the first one, he would have to dedicate his calculating prowess to it and it wouldn't be idle when Sona is still in the middle of the unknown ritual.
'I can leave the Descorrer alone once activated so let's focus on securing Sona first before anything else.' With that in mind, Kisuke out Benihime in her Shikai form. However, those who have seen this blade of his before would notice that everything about it seems pale in comparison to the last time he took it out. Yoruichi knew that reason for this and only took a quick glance at it before resuming her killing spree.
Nyx doesn't care about the Grim Reapers being massacred and only focus on what she thinks a threat, "Hohh~, Interesting... That mask... is not an artifact... but what is it?" She muttered.
Since he's still analyzing Sona's situation from afar, he's not in the mood to talk to his enemies like he used to and only waved Benihime towards her, sending a whistling, blood-red energy wave.
Nyx only sneered at his attempt and summoned a cloud of dark aura in front of her to meet the energy wave. After deflecting it away, she saw that the masked man is only staring at her, "What? Done already? That guy and Hades put a lot of attention to you, but is that all you can do? How disappointing."
Kisuke didn't respond and only shifted his gaze around from time to time. When Nyx is about to lose her patience, Kisuke suddenly started barraging her with waves and waves of the same attack as before. And Nyx only did the same thing, deflecting his attacks everywhere.
"What's this? Are you even trying? From what I heard, it seems that you're pretty close to that Devil and I thought you'd be more desperate." Kisuke still chooses not to respond to anything she said and kept attacking and attacking. All the blood-red arcs of energy flew in a random direction and when it hit the wall, ceiling or the floor, it only left a small nick, a testament on how resistant to damage the entire hall is.
Pluto only watched from the sidelines and when he saw that Yoruichi is almost done killing the Grim Reapers, he commented, "It's no use. The ritual is already half done and even if you kill everyone here, it'll only slow down the process. You can also just choose to drag that Devil off the pedestal but it'll only slice her to pieces since her blood is already bounded with the magic circle."
Just like Kisuke, Yoruichi didn't respond and only continued killing everyone working on the ritual.
"What's up with these two? Are they trying to buy time? Don't get your hopes up since the moment you entered this space, no one is allowed to exit or enter until the two of you are dead." Nyx tried to get guess their intention but she still wasn't able to get a different reaction and she's starting to lose her patience, "Hades sent me here to deal with you and even asked me to use 'that' to make sure you're dead. I don't know what he has against you, but he overestimated you."
Yoruichi is already on the last Grim Reaper and taking that as a cue, Kisuke instantly changes gears. For the first time since entering this space, Kisuke let loose the massive killing intent he has been keeping.
This change in demeanor caught Nyx off guard and she wasn't able to react fast enough when Kisuke suddenly appeared in front of her and swung down his blade. She was able to back off but she sustained a large wound across her chest, spurting out blood everywhere.
Pluto was also shocked at this scene and tried to help Nyx escape, but before he could do so, Yoruichi suddenly appeared behind him with her heels dropping down on him so he has no choice but to raise his arms to defend himself. However, he underestimated the force behind her ax kick as it immediately broke both of his arms and he dropped down from the air like a meteor. Landing on the floor back first, Pluto coughs out blood but he didn't wait there and immediately got out of the way with another attack from Yoruichi.
He didn't want to underestimate her strength anymore and dodge her attack which was confirmed to be a good call when he saw minutes of cracks appearing on the floor when her fist hit it. He knew how durable the floor where the magic circle is sitting and even he has all day, he wouldn't be able to destroy it. When he took a closer look at his assailant, he noticed something different as six drums made out of lightning were hovering behind her which made him remind of the God of Thunder.
Hence, the battle between the God of Thunder and the Ultimate Class Grim Reaper begun.
On Kisuke side, he's defending against Nyx's bullets made out of darkness by deflecting it to the side like what she's doing earlier while also decreasing the distance between them, 'Dammit! How the hell is this guy so strong all of a sudden? Pretending to be weak? But why?'
Although Nyx has a lot of questions, she became careful and started to take him seriously. Seeing that her bullets don't have much effect, the dark aura around her started spinning and panning out, engulfing everything in its way. Kisuke stopped for a bit to observe what is this before turning around to leave, "Hey! Where are you going?" The cloud of darkness spun and formed into spears, launching towards Kisuke.
Kisuke then turned around and pointed his finger towards Nyx, "Juugeki Byakurai (Heavy-Strike Pale Lightning)..." With a mutter, a dark red beam of light, more than an inch of diameter, suddenly manifested in front of his finger. The beam caught Nyx off guard again but she's was still able to react, though her shoulder was pierced by it, "Tch! You sure have a lot of tricks under that hat!"
Nyx took a quick glance at her wound to see if there is anything amiss, which she confirmed that it's only a small normal wound. She looked back to Kisuke and noticed that he's already beside the Devil, but instead of stopping and following him, she only sneered at him, "Didn't you hear? Forcefully pulling her out would only kill her much faster."
Kisuke ignored her once again and swung his blade towards a certain direction, letting off another blood-red sword wave and it hit a certain part of the magic circle, however, just like what happened earlier, it only left a small crack on the floor, "What? Trying to destroy the magic circle? Although it'll really save her, you would need to destroy this entire place for you to succ-- What!?"
The light of the magic circle started dimming, ceasing its function.