Tyrant from regimental HQ around the South (6)
I believe the answer is:
despot
'tyrant' is the definition.
('despot' can be a synonym of 'tyrant')
'regimental hq around the south' is the wordplay.
'regimental hq' becomes 'depot' (I've seen this before).
'around' indicates putting letters inside.
'the south' becomes 's' ('S' can be a synonym of 'south').
'depot' placed around 's' is 'DESPOT'.
'from' is the link.
(Other definitions for despot that I've seen before include "Cruel and oppressive dictator" , "A ruler with unrestricted power" , "Posted to tryant" , "Posted by tyrant" , "who treats others badly?" .)