There is a candle that represents the power of the magic inherited in this family from generation to generation, but it looks like the flame on the candle is going out.
この場合、次のような言い方ができますよ。
ーThere is a candle that represents the power of the magic inherited in this family from generation to generation, but it looks like the flame on the candle is going out.
「この家族に代々受け継がれた魔法の力を示すキャンドルがあるんだけれど、そのキャンドルの火が消えようとしている」
a candle that represents the power of the magic で「魔法の力を示すキャンドル」
inherited from generation to generation で「代々受け継がれた」
ご参考まで!