On the night Gyokko was slain.
Muzan's stronghold-the Infinity Castle.
This was a subterranean pocket dimension created by Nakime's Blood Demon Art. She could control it at will and establish portals at certain fixed locations, allowing two-way travel between the Infinity Castle and those destinations.
After more than a century, the Demon King Muzan had summoned the Upper Ranks here once again.
At the center of this castle, which seemed pieced together from countless buildings like stacked blocks and could be freely dismantled and reassembled at Nakime's will, an open platform hovered in the air.
With her hair covering the upper half of her face, Nakime sat quietly on a platform at the edge, a biwa cradled in her arms. Her hair spread out behind her into the gaps between the buildings, as though the entire Infinity Castle were an extension of her body.
"Twang."
The pick in Nakime's hand brushed lightly across a string, and a demon with cold, pale skin covered in dark teal stripes appeared on the platform.
He had short, peach-pink hair and wore a sleeveless cropped shirt of a similar color, with white shorts below. His golden eyes bore the words "Upper Rank" and "Three," respectively, proclaiming his identity-Upper Rank Three, Akaza.
At that moment, Akaza merely stood quietly on the platform without a word.
The Upper Ranks had been summoned to the Infinity Castle again after more than a century. That meant an Upper Rank had been killed.
But his first thought was not that an Upper Rank had fallen to the Demon Slayer Corps. Instead, he assumed some demon who had grown powerful had killed one of the Upper Ranks in a rank replacement blood battle.
After all, since becoming a demon, he had never heard of an Upper Rank dying at the