Path to Power

After explaining the power levels and basic cultivation to Rai , Akasa continues by giving the option to either continue staying the castle which was an universe level artifact where he could build a solid foundation and start his cultivation or he could be teleported to the Kaminari clan where he would be treated as a prince as he was the inheritor of the clan's founding patriarch (although a prince with no power and cultivation). 

Rai obviously chose to stay in the castle as he realized that he would receive various envious threats when the clan realizes that a nobody like him had inherited their founder's inheritance .He felt his surroundings go black just as he felt when he was hit by the truck on earth. He realized that he was just teleported and opened his eyes to see another large hall with tall steles with weird symbols on them . He asks Akasa where he was and Akasa replies by saying that the castle had been designed as the training ground of the inheritor by master Akihiko who was an ancient level artifact refiner . The castle had specialized rooms for resting , cultivation hall , smithery , medical garden , library and a treasury. He was in the cultivation hall and the steles were dao steles with different daos embedded in them . As Akasa was explaining the various daos , Rai was attracted to a special dao which had slashed on them . On seeing them , Rai had deciphered them as sword slashes as he was very familiar with the sword due to the knowledge bestowed upon him when his physique evolved. 

Rai completely ignored Akasa's explanation and tried to focus on the slashes when he entered a state of enlightment where he sees his master Akihiko surrounded by thunder and looked like a god of thunder and executing a complex set of sword moves where he cleaved through the enemies effortlessly as their bodies collapsed . He felt his blood boil seeing his master fight so elegantly without being stained even with a drop of blood on his pristine white robes. He had totally forgotten the beautiful red sword whose recognition he had obtained and ran towards the weapon section to grab a sword and started copying his master .

Rai perfectly copied his master's moves but he felt something missing , something very essential . He felt that the moves were lacking something and his mind started to find the solution for the problem . On the other hand , Akasa which was continuing its explanation on Daos stopped when it sensed Rai running towards the weapon section to grab a sword . It was angry but then seeing Rai executing his master's moves made it giggle as he understood what made Rai so distracted. Akasa was enjoying the scenario where Rai was constantly frowning as he couldn't fathom what the moves very missing . On seeing his frustration , Akasa felt it needed to guide him when it saw Rai suddenly stop and gather all the mana in the room . Through his sheer will , he pulled all the mana towards him and understood the mana flow of the first move and executed it . Even though it was just a vertical slash ,he comprehended the intent behind it and executed the move which completely shocked Akasa . It felt that Rai's physique was just a cheat when it came to anything related to a sword. 

Rai felt jubilant on executing the move perfectly but just crashed when the exhaustion hit him. He felt so devasted as if he was on the verge of dying . Akasa suddenly intervened when it asked him to drink a strange drink which appeared in his hands . Rai immediately felt relief and asked Akasa what happened . It felt like sighing and replied " Master , though I am thoroughly impressed as you could execute master Akihiko's move on your first try , you have to remember that you are a person who has yet to enter body tempering realm and you just executed a sage level weapon art which was developed by master Akihiko when he just became a sword sage . You have to know that even mahayana realm cultivators don't use sage level arts due its mana consumption. So you master who had no mana just burnt his will to order the mana in the surroundings to move according to the mana flow of the move , which exhausted your will and you were about to die if I hadn't made you drink the will rejuvenation potion . Rai felt foolish as he almost ended his journey without even starting it .

Akasa continues by saying "Though you were on the verge of death , you became the first in the cosmos to become a sword apprentice after performing a sword move just one time even your master who was touted as the greatest sword user took three days to comprehend an intent to become an apprentice." It sounded very calm but only Akasa was freaking out inwardly when it remembered the events which just took place before its eyes and thought " The cosmos will be getting a sword monarch very soon ."

Sword dao levels(or any weapon levels)

Sword apprentice - Sword master - Sword grandmaster - Sword king - Sword Emperor - Sword sage - Sword monarch