From Destinypedia, the Destiny wiki
Darbi 55-30 is a Frame Postmaster based within The Farm. Like its predecessors, Darbi stores messages for incoming Guardians and will reward Guardians for certain acts. As an example, Darbi will reward Guardians with a rare material or Glimmer for completing a gold-tier Public Event. Darbi will also collect any Engrams a Guardian might have missed in their last mission.
List of appearances