Blood of the gods and some rich old royal (5)
I believe the answer is:
ichor
'blood of the gods' is the definition.
(I've seen this in another clue)
'some rich old royal' is the wordplay.
'some rich' becomes 'ich' (I can't justify this - if you can you should believe this answer much more).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'royal' becomes 'r' (abbreviation).
'ich'+'o'+'r'='ICHOR'
'and' is the link.
Can you help me to learn more?
(Other definitions for ichor that I've seen before include "Choir (anag) - fluid that flows in the veins of the gods" , "Fabulous flower" , "Fluid in divine veins" , "Blood of the gods found in choir" , "Superior blood" .)