After calming himself down a little and emptying his mind, Raymond sat down cross-legged on his bed and concentrated. According to the Blue Wind True Art that he was practising, the energy centre that a cultivator opened could be divided into nine different ranks according to its capacity. A Rank-1 energy centre was the pinnacle, whilst Rank-9 was the worst. The majority of cultivators who stepped onto the spirit-refinement path were people that relied on external treasures or medicine after already having exhausted their potential. These people usually opened up a Rank-9 energy centre and didn't advance much afterwards.