Casts off, carrying king in rags ... (6)
I believe the answer is:
shreds
'rags' is the definition.
('shred' can be a synonym of 'rag')
'casts off carrying king' is the wordplay.
'casts off' becomes 'sheds' ('shed' can be a synonym of 'cast off').
'carrying' means one lot of letters goes inside another.
'king' becomes 'r' (r is abbreviation for rex).
'sheds' placed around 'r' is 'SHREDS'.
'in' is the link.
(Other definitions for shreds that I've seen before include "Torn pieces and tatters" , "Small pieces, maybe of bread" , "Scraps - fragments (of evidence?)" , "Tears into tiny pieces" , "Tears into small pieces" .)