Forerunner; proclaimer (6)
I believe the answer is:
herald
I believe this is a double definition.
'forerunner' is the first definition.
(I know that forerunner can be written as herald)
'proclaimer' is the second definition.
(I've seen this before)
(Other definitions for herald that I've seen before include "Proclaimer" , "Signal the arrival of" , "Ceremonial messenger" , "Harbinger, messenger" , "Usher in; proclaim" .)