BD as well as others right on this thread already explained that point. Who is it you think created the Septuagint and why did they? And then, to what version of it are you referring? Do you know the actual history of it?
The Holy Ghost.
from thy infancy thou hast known the holy scriptures, which can instruct thee to salvation, by the faith which is in Christ Jesus. All scripture, inspired of God, is profitable to teach, to reprove, to correct, to instruct in justice, That the man of God may be perfect, furnished to every good work. (2 Timothy 3:15-17)