Tyrant finds son in warehouse (6)
I believe the answer is:
despot
'tyrant' is the definition.
(I know that tyrant can be written as despot)
'son in warehouse' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'in' means one lot of letters goes inside another.
'warehouse' becomes 'depot' (I've seen this before).
's' going into 'depot' is 'DESPOT'.
'finds' acts as a link.
(Other definitions for despot that I've seen before include "Cruel and oppressive dictator" , "Arbitrary ruler" , "Posted to tryant" , "Cruel absolute ruler" , "nasty ruler?" .)