party; set; gang; company; person
「徒」 has other readings with different meanings.
ordinary; common; usual
vain; futile; transient; frivolous
imprisonment (for 1-3 years; third most severe of the five ritsuryō punishments)
foot soldier (Edo period); samurai on foot
彼はその宗教の徒だと聞いたよ。
I heard he's a follower of that religion.
仏教の徒として生きていきたい。
I want to live as a Buddhist.
キリスト教の徒が集まっていた。
Christians had gathered.