One of the Asura giants said in shock, "The Saint Concubine and the other younger disciples have also boarded the Sun Chariot, but that was only possible because they had the leader's charm to ward off the demon sunfire. This brawny young man doesn't have the leader's charm and can board the Sun Chariot solely on his own, this is really incredible! Could it be that he has already attained the heavenly demon god-level demon sunfire?"
Cultivation base wasn't the only requirement one needed to board the Sun Chariot, even demon magnates would be incinerated by the demon sunfire if they didn't have a strong attainment in the demon sunfire. Not even their soul weapons could save their lives.
In turn, if one's attainments in the demon sunfire were as strong as the heavenly demon god's, they would be able to walk onto the Sun Chariot and acquire a stronger, better heritage.