I just realized something of the 24-hour returner skill. If he dies of old age, he'll just return 24 hours before he dies. I wonder...does this count as an eternal prison locked only on that timeline? He can return to the past by making the same suicide attempt, but he can never truly be free from that world's timeline. I guess the only way to be free is to finish the tower so all the magic and skills will be gone...this plot reminds me of the movie "Edge of Tomorrow."