And so, sir, is it including the Egyptian god of the underworld? (6)
I believe the answer is:
osiris
'the egyptian god of the underworld?' is the definition.
(I've seen this before)
'and so sir is it' is the wordplay.
'OSIRIS' is hidden in amongst the letters.
However, I am unsure how this is indicated.
'including' acts as a link.
Can you help me to learn more?
(Other definitions for osiris that I've seen before include "dead judge?" , "one held to be divine" , "Egyptian god of the underworld" , "Egyptian deity" , "God, husband of Isis" .)