Tournament of Astros: End of Second Day
Although Souta was strong, he was still at the level of initial rank. Level 61 to 65 were considered initial, level 66 to 70 were intermediate, level 71 to 75 were high, and lastly, level 76 to 80 were peak.
That's just how the game divided the power levels.
He was only level 64 close to the intermediate rank. Regardless of his level, his combat prowess was higher due to him possessing various skills, equipment, and the benefits he received from the system. It made other people think that his aura was already at high rank of fourth stage.
Honestly, it's not really a high rank. It was a level between intermediate and high. In short, Souta's base power was already stronger than intermediate fourth stage but weaker than the high fourth stage. It was a huge improvement in his power and normal One Shackle Realm wouldn't be a problem for him. Only those experts at Two Shackles and above could give him trouble.