I would say that South Node Ketu is more like a reverse-obsession, rather than an absence. It is the destiny that is thrust upon you, that you do not want. Ketu shows the thing that disgusts and revolts you the most. My mother was born during a solar eclipse caused by Ketu in Virgo. What she despised more than any other , was low-class people. She was racist and anti-semitic, as most people of her generation were. But she reserved her bitterest scorn for "white trash." Her arrogance was her fatal flaw.