At the same time, maintaining the operation of the Time Domain would also require support of a gigantic mana source. The power that humans could obtain from it did not appear out of thin air, either. Lin Li ended up using up more than 10 Legendary magical crystals when he used the Time Domain to hone the cooperation and tacit understanding between the mages. If the Caesar Family wanted to use the Time Domain to produce powerhouses in batches, they'd end up using up more than just 10-odd Legendary magical crystals.
Besides, there was another problem. Obtaining power through such a method might not necessarily be a good thing for mages. Due to the huge difference in the passage of time, the mages' abilities and strength would not be improved in the outside world once they left the Time Domain. If they wanted to continue improving their strength, they would have to enter the Time Domain again. That might be considered a form of dependence or addiction.
