"The benefits of becoming an official disciple of the Fierce Bird Sect are indeed quite good, I'm afraid that just by eating in this canteen every day, after a year or half a year, my entire physique will be greatly enhanced. Master said that there are even higher-level medicated meals in the canteen, but they are only provided to the six core disciples and the elders of the school..."
The so-called six core disciples is a division within the Fierce Bird Sect.
Simply put, they are the six strongest disciples among all the disciples of the Fierce Bird Sect. They refer to each other as senior or junior brothers and sisters.
Moreover, all the other disciples have to address these six as senior brother or sister, regardless of whether their seniority or age is greater than theirs.
Reserves, official disciples, elite disciples, core disciples.
These are the four levels within the Fierce Bird Sect.