Is, from the first, into deviant sex (6)
I believe the answer is:
exists
'is from' is the definition.
The answer and definition can be both to do with fundamental existence as well as being verbs in their -s form.
Perhaps there's a link between them I don't understand?
'first into deviant sex' is the wordplay.
'first' becomes 'ist' (ist resembles 1st).
'into' means one lot of letters goes inside another.
'deviant' indicates an anagram.
'sex' anagrammed gives 'exs'.
'ist' placed within 'exs' is 'EXISTS'.
'the' is the link.
Can you help me to learn more?
(Other definitions for exists that I've seen before include "Is present in the universe" , "Has life" , "Lives" , "Is extant" , "Has objective reality" .)