He again is in attendance (4)
I believe the answer is:
here
'in attendance' is the definition.
(I've seen this before)
'he again' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'he'+'re'='HERE'
'is' is the link.
(Other definitions for here that I've seen before include "On this spot" , "Hither" , "The present location" , "final clue?" , "To hand" .)