Destiny of king is fulfilled (6)
I believe the answer is:
kismet
'destiny' is the definition.
(kismet is a kind of destiny)
'king is fulfilled' is the wordplay.
'king' becomes 'K' (abbreviation for king in chess).
'fulfilled' becomes 'met' ('meet' can be a synonym of 'fulfill').
'k'+'is'+'met'='KISMET'
'of' acts as a link.
(Other definitions for kismet that I've seen before include "Destiny; 50s musical" , "fortune" , "Turkish fate, destiny" , "Broadway musical" , "Fate - 1953 musical" .)