Di Ku's mentor was a peak-level powerhouse in the Immortal Great Freedom Realm. He was killed by a traitor, but before he died, he turned his life's cultivation into nine Dao Fruits and sealed them in Di Ku's sea of consciousness. Once Di Ku finds a clone of a Dao Fruit, he can unlock it and inherit one-ninth of his mentor's strength. When all the Dao Fruits are unlocked, he will inherit his mentor's full power. Then he can avenge his mentor... and eventually become the Lord of the Universe.
