Emperor in love with us is demanding (7)
I believe the answer is:
onerous
'is demanding' is the definition.
(I've seen this before)
'emperor in love with us' is the wordplay.
'emperor' becomes 'nero' (Roman emperor).
'in' is an insertion indicator.
'love' becomes 'o' (love means zero in tennis).
'with' is a charade indicator (letters next to each other).
'o'+'us'='ous'
'nero' placed within 'ous' is 'ONEROUS'.
(Other definitions for onerous that I've seen before include "Burdensome, weighty" , "Burdensome, taxing" , "Involving much effort" , "Effortful" , "Involving much work" .)