Bleach: From the moment I was invited by Squad Zero

In the age of declining magic, the genius mage Yanagawa, while researching supermagic, unexpectedly falls into the world of the Grim Reaper. Having been reborn, the naturally unassuming Yanagawa only wishes to live a peaceful life and incidentally reach the supreme realm that his previous life's limitations prevented him from attaining. —Until one ordinary day, a bald monk calling himself "Hyosube Ichibei" appears before him… From then on, the nightmare of the Central 46 Chambers is about to begin.