The Fremen see her as the Earth Figure, a demi-goddess whose special charge
is to protect the tribes through her powers of violence. She is Reverend
Mother to their Reverend Mothers. To pilgrims who seeks her out with
demands that she restore virility or make the barren fruitful, she is a
form of antimentat. She feeds on that proof that the "analytic" has limits.
She represents ultimate tension. She is the virgin-harlot -- witty, vulgar,
cruel, as destructive in her whims as a coriolis storm.

as taken from The Irulan Report