Leading characters in rifts (5)
I believe the answer is:
first
'leading' is the definition.
(I've seen this in another clue)
'characters in rifts' is the wordplay.
'characters in' is an anagram indicator.
'rifts' with letters rearranged gives 'FIRST'.
(Other definitions for first that I've seen before include "Prime" , "Cardinal" , "Earliest; good degree" , "Coming before all others" , "Premier (except in football!)" .)