Each person in it has some very onerous duties (8)
I believe the answer is:
everyone
'it has some very onerous duties' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'each person' is the wordplay.
'each' becomes 'every' (synonyms).
'person' becomes 'one' ('one' can mean an unspecified person).
'every'+'one'='EVERYONE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for everyone that I've seen before include "Uncle Tom Cobleigh and all" , "the masses" , "All without exception" , "Entire group" , "All and sundry" .)