Last days at the azure sky planet (part 10)
But then the leader discarded his previous assumption, the spirit energy he could feel coming from the black-haired youth, was only that of a stellar constellation cultivator, so it didn't make sense that he a mortal transcending cultivator was outclassed in spirit energy terms.
Also remembering the terrifying murderous intent of earlier he reached more logic conclusion, he was in front of a rare cultivator which focused in the soul path first, probably reaching an equivalent to the sea of knowledge realm as a soul cultivator, before starting to cultivate in the energy path.
That would explain the low cultivation in the energy path but with an incredibly strong spirit pressure and a lot of enemies which had fallen under his sword creating that terrifying murderous intent.
As for Aster's young appearance, that was intransigent, strong cultivators remained young although their ages were on the six digits, so a few thousands of years of age weren't enough to be considered old.