This character is in a devious plot (6)
I believe the answer is:
pistol
'this character' is the definition.
(I have seen 'Shakespearean character' mean 'pistol' so perhaps 'character' could also mean 'pistol')
'is in a devious plot' is the wordplay.
'in' means one lot of letters goes inside another.
'a devious' indicates an anagram.
'plot' anagrammed gives 'ptol'.
'is' put within 'ptol' is 'PISTOL'.
(Other definitions for pistol that I've seen before include "Shakespearean - weapon" , "Hand weapon" , "potential killer?" , "Piece" , "Arm" .)