Dubbed 'King of Darkness' by journalist (8)
I believe the answer is:
knighted
'dubbed' is the definition.
('knight' can be a synonym of 'dub')
'king of darkness by journalist' is the wordplay.
'king of' becomes 'k' (I am not sure about this - if you are sure you should believe this answer much more).
'darkness' becomes 'night' (night is a period of darkness).
'by' means one lot of letters go next to another.
'journalist' becomes 'ed' (short for editor).
'k'+'night'+'ed'='KNIGHTED'
Can you help me to learn more?
(Other definitions for knighted that I've seen before include "Dubbed 'Sir'" , "Given a title" , "Made a Sir" , "Given an honour" .)