A breakthrough to Ancient Sage required Aeon of Ancient Sage, but this energy was everywhere in the Azure, so it wasn't a concern at all. However, a breakthrough to this realm was much more than just having the required amount of energy. Just like his breakthrough to Zongshi realm back then, it required one to have sufficient accumulation.
Dan Xiaotian's talents and mental resilience were decent, but he lacked accumulation.
If they had another month's time, Dan Xiaotian would surely be able to make a breakthrough even without relying on any artifacts or special processes, but one's age waited for no one. Dan Xiaotian was on the verge of reaching seventeen soon, and once the momentum fully died down, all hopes would be dashed.
"Swallow it!"
Zhang Xuan took a deep breath slitting his own wrist with his sword qi. Blood spurted out like a fountain, but he quickly gathered the blood together into a sphere before delivering it into Dan Xiaotian's mouth.