This is the advantage of choosing a mentor, the resources in the mentor's guarded area.
The cultivation resources required for cultivating techniques are produced in the mentor's guarded area.
For instance, the Life and Death Fruit that Lu Sheng exchanged is a special product within the Life Factions, harvested from a planet called Kurong Star. It's an excellent cultivation resource to assist in cultivating the "Life and Death Technique."
"Besides this, there's also the 'Undying Technique' that Second Senior Brother mentioned."
Lu Sheng glanced at the price of the 'Undying Technique' in the list.
"Planet-level Martial Art: Undying Technique. Cost: 500 credits!"
"Phew!"
Seeing that price, Lu Sheng gasped.
After purchasing the Inner Cave Heaven and the Sky-controlling Martial Arts, he also bought an explanation of planet-level knowledge and asked Second Senior Brother for advice.
Now, he only had 439 credits left.
He couldn't exchange for the 'Undying Technique.'
