Ruler's occult arts (4)

I believe the answer is:

tsar

'ruler's' is the definition.
(tsar is a kind of ruler)

'occult arts' is the wordplay.
'occult' indicates an anagram (a strange or occult ordering of the letters).
'arts' is an anagram of 'TSAR'.

(Other definitions for tsar that I've seen before include "Despot" , "Monarch of old Russia" , "Russian monarch" , "Old Russian ruler" , "Nicholas II was the last" .)

I've seen this clue in The Guardian.

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