Family almost broken by contrary leader in unscrupulous monster, Roman emperor (8)
I believe the answer is:
caligula
'roman emperor' is the definition.
(I've seen this before)
'family almost broken by contrary leader in unscrupulous' is the wordplay.
'family' becomes 'clan' (clan can mean a large family).
'almost' means to remove the last letter (most of the word but not all of it).
'broken by' is an insertion indicator (inserted letters break into the word).
'contrary' becomes 'alig' (I can't justify this - if you can you should give a lot more credence to this answer).
'leader in' indicates taking the first letters.
The initial letter of 'unscrupulous' is 'u'.
'clan' with its final letter taken away is 'cla'.
'alig'+'u'='aligu'
'cla' going around 'aligu' is 'CALIGULA'.
'monster' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for caligula that I've seen before include "Successor to Tiberius" , "imperial figure" , "Emperor who threatened to make his horse a Consul" , "Third Roman emperor" , "Roman emperor, notorious for his cruelty" .)