If their believers don't pray frequently, then they will be on their way to death. As it is, they had spent a little more than 600 DE in their fights. It is a little more than the total DE of a single clone and about 12.8% of their total DE. That expenditure was just in a few hours of fighting, but they are already running out of prayers to replenish it.
As it is, they can only look forward to the evening prayers to get another bump in their supply of prayers. They may have a lot of DE between them, but they won't be able to replenish it if their expenditure increases more than their current rate.
It is because while they have access to each other's DE, they have the same believers. A single god would be content with the amount of prayers they are getting, but it is not nearly enough for 9 of them.
Legion-9 said with optimism, "At the very least, we should be getting more prayers soon. War always increases the faith of believers."