Malevolent deity is restrained reportedly (4)
I believe the answer is:
loki
'malevolent deity' is the definition.
(Norse trickster god)
'restrained reportedly' is the wordplay.
'restrained' becomes 'lowkey' (I've seen this before).
'reportedly' indicates a 'sounds like' (homophone) clue.
'lowkey' sounds like 'LOKI'.
'is' is the link.
(Other definitions for loki that I've seen before include "Norse god of mischief" , "Gossip" .)