Three months of training with the heavy wooden sword. After three months of training Ender's body to the limits and beyond his body met the minimum requirements to store the World's Energy to become ether.
Something he was not sure he could be considered a blessing or a curse was that Percy received a wooden sword for his birthday and challenged Ender. Of course Ender went easy on Percy however would always get up and when he lost he would come back a few days later to challenge him. In between Percy would drag Ender around to play as well but that decreased. Alice in returned was less tired because she was not going around as often.
Ender was excited yet troubled by his development of nearing a breaking through. With his knowledge breaking through to straight to Low Black Core however it would cause a disturbance on some kind. In his memories when Demon King Izrath broke through his room was nearly destroyed.
If Ender was to try to break through at home or in the village it would cause a disturbance drawing attention. Ender needs to get out of the village and find somewhere no one would notice him. Now that Ender thought about it when he is dragged around the village to south some distance seem to be a forest.
If Ender could enter that forest and find an isolated place it would be perfect. But how? Ender thought for while before realizing something he had overlooked. Ender was 4 years old so he could just go out to "explore" if he really asked and begged.
The next day Ender did as he planned and asked his mother Millie if he could go exploring. Not thinking much since Ender has not requested much as child and the village is relativity safe agreed. Ender quickly went to get his wooden sword before quickly running around the village. Why around? To ensure no one would know where he was going.
After running around the village a few times Ender slipped out of line sight and he went south at his top speed. Not caring if he got tired he wanted to enter the forest before it was noon. The run to the forest shorten but he ended up out of breath. Taking a minute to catch his breath Ender started to wander around the forest to find a place that was secluded.
After about an hour of searching Ender found a large tree that towered higher than all of the others. At the top was a branch that looked to sturdy enough to hold him. Climbing the tree was easy except for the first branch which he struggle to reach. After another 15 minutes of climbing Ender reached the branch.
After Ender regulated his breathing he started to focus on using the Demon King's Cultivation Technique. Like a vortex Ender started to bring in the World's Energy. He opened all his pores as a way draw in the World's Energy. As it entered energy rapidly turned into a gaseous ether in Ender's body his limit was quickly being reached. The trees in forest started to sway to and fro as the World's Energy passed by. The tree started to creak from the pressure being emitted.
"Not yet! Not yet, limits are meant to be met and acceded!" Inside Ender's mind he was screaming. Enders body started to feel bloated as if he was about to explode. Knowing if he pushed himself any further he really would explode Ender decide to stop absorbing and begin solidifying his energy core.
Different from normal cultivating technique the revised Demon King's Cultivation Technique did not have one core but seven cores in the body. The locations are the soles of the feet, near the stomach, in the heart, the palm of the hands, and in the center of the brows. By creating the cores at the start instead of later it would cause less disturbances. The only difference is that advancing would be that much harder since 7 cores would be difficult to equally advance. However the original Demon King Cultivation Technique also had a way of making advancing easy by creating a constant cortex at the cores so that ether could be rapidly made.
Separating the ether in the body was one of the most difficult step in the process. As Ender separated the ether it felt like thousands of knives were ripping him apart from the inside. Biting down on his teeth so that he would not accidently bite his tongue Ender persisted. Like this time slowly crawled by until noon arrived.
After an agonizing experience Ender was finally able to separate the ether into seven the core region. All that was left was to slowly create the cores and make them spin like a vortex so that they could continuously absorb the World's Energy. However, all the cores spin in different ways creating tornado like flows where they meet.
Those tornados were destroying his body from the inside out. If Ender did not strengthen his body like he did the past few years his body would have been ripped apart. Ender had to quickly create this cores or his body would not hold out.
Like a tempest Ender rapidly pored all his will into creating the cores. Then all movement stopped. The world's energy. The trees. Everything. Then with an explosion with Ender at the center a small shockwave of ether was released.
All seven cores were created. Ender last thoughts before passing out was that his efforts were worth not wasted.