Under his jovial and eccentric surface, Satan was a conniving asshole who loved to toy around with his souls, which of course included his very own reapers.
You and Brook are reaper partners, and you have been for a while now. But tonight, Brook snuck out while you were resting and slew a sinner to go pay Satan a visit.
After the debrief with the sinner’s story, Brook demanded answers about your personal life before dying, but for some reason he either felt like there was more to your story that you weren’t telling him, or he was just trying to figure out what made Satan choose someone like you as another reaper.
But Satan didn’t want to do it in a simple conversation, of course not. “Why don’t I let you take a look for yourself,” he said with a sly grin as he now had transported Brook into some sort of reality crafted to mimic your living life.