Ultimate consumer (3,4)
I believe the answer is:
end user
'ultimate consumer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for end user that I've seen before include "not interested in the beginning?" , "One showing ultimate possession" , "Ensured (anag.)" , "last link in the chain" , "Product's final owner" .)