Dark and twisted, first king abdicates (4)
I believe the answer is:
inky
'dark' is the definition.
(thesaurus)
'and twisted first king abdicates' is the wordplay.
I cannot quite understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
'first' could be 'i' (I in Roman numerals eg Elizabeth I) and 'i' is found in the answer.
'king' could be 'k' and 'k' is found within the answer.
A single letter 'y' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
(Other definitions for inky that I've seen before include "Marked by leaky pen" , "Like the printing trade" , "Like writing fluid" , "Black as pen fluid?" , "Coloured black" .)