The prison was shrouded in perpetual darkness, with no distinction between day and night.
Therefore, Bartlett could only use the frequency of meal deliveries as a measure of how long he had been in this hellish place. The devils did not provide meals for their prisoners in a three-meals-a-day fashion, but the interval between each meal was quite regular, making it a somewhat reliable method.
This method was not something the barbarian had come up with himself but was taught to him by the soul merchant 'Elvis'.
This easy-going fellow didn't seem too worried about his situation. According to him, soul merchants would try to rescue their trapped colleagues because it was a dangerous profession, and nobody could guarantee that they'd always be safe. So everyone voluntarily abided by this industry rule.
