Do come back in Scandinavian mythology as a supreme god (4)
I believe the answer is:
odin
'god' is the definition.
(Norse god)
'do come back in' is the wordplay.
'do come' becomes 'do' ('do' can be a synonym of 'come').
'back' says the letters should be written in reverse.
'do' written backwards gives 'od'.
'od'+'in'='ODIN'
'scandinavian mythology as a supreme' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for odin that I've seen before include "Scandinavian war god" , "God - I nod (anag)" , "Legendary Scandinavian" , "Norse god, husband of Frigg, father of Thor" , "Supreme Norse deity" .)