GateKeeper is not a guide unless it means something different in the Wiccan community then the Witch one. Gatekeeper is either keeping the viel between the dead and the living and also keeping the viel between this world and the Fae.
There a very strong spirit they have to be they are like Soldiers keeping things the way there supposed to be.
When I wish to commune with the dead or ask for assistance from the Fae I will leave a offering for the Gatekeeper that allowed this interaction to begin with. Hope this sort of explains what there purpose is and what they are a little better.