Newcomers hold sway in rival Resistance at the start of struggle (10)

'newcomers' is the definition.
The answer and definition can be both people as well as being plural nouns.
Maybe there's an association between them I don't understand?

'hold sway in rival resistance at the start of struggle' is the wordplay.
'hold sway' becomes 'reign' (I've seen this before).
'in' is an insertion indicator.
'rival' becomes 'foe' (foe is a kind of rival**).
'resistance' becomes 'r' (abbreviation).
'at the start of' suggests taking the first letters (I've seen 'at the start' mean this).
The initial letter of 'struggle' is 's'.
'reign' going within 'foe' is 'foreigne'.
'foreigne'+'r'+'s'='FOREIGNERS'

Can you help me to learn more?