RE: Zero -Starting Life in Another World-, Vol. 25 (Light Novel): Volume 25 - Tappei Nagatsuki

Subaru Natsuki is determined to make it through the Pleiades Tower without losing anyone, and he's willing to die however many times it takes. It's going to take more than just guts to get everyone out and Subaru's still only one man. Luckily, his friends won't let him brave the challenges of the tower alone. And then it appears--his own book of the dead, a record of pasts that never came to be...