... crank up Greek character I've seen with intro of drums (7)
I believe the answer is:
deviate
'crank' is the definition.
(another term for deviant)
'up greek character i've seen with intro of drums' is the wordplay.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'greek character' becomes 'eta' (letter from the Greek alphabet).
'seen with' says to put letters next to each other.
'intro of' says to take the initial letters.
The first letter of 'drums' is 'd'.
'eta'+'ive'+'d'='etaived'
'etaived' reversed gives 'DEVIATE'.
(Other definitions for deviate that I've seen before include "Go off track" , "Turn aside or digress from" , "Depart from an established course" , "Turn away" , "Turn aside from accepted way" .)