He generates huge interest seizing power — Richard III? (7)
I believe the answer is:
usurper
'richard iii?' is the definition.
(Richard III usurped the throne)
'he generates huge interest seizing power' is the wordplay.
'he generates huge interest' becomes 'usurer' (someone who sets high interest rates).
'seizing' is an insertion indicator.
'power' becomes 'p'.
'usurer' enclosing 'p' is 'USURPER'.
(Other definitions for usurper that I've seen before include "One who takes power or position wrongfully" , "One seizing power illegally" , "replacing person" , "Illegal seizer of power" , "Pursuer of one who takes power wrongfully (7)" .)