Individuals and characters turning up in verbose non-fiction (4)
I believe the answer is:
ones
'individuals' is the definition.
(I've seen this before)
'up in verbose non-fiction' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'in' indicates a hidden word.
'seno' can be found hidden inside 'verbose non fiction'.
'seno' back-to-front is 'ONES'.
'and characters turning' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for ones that I've seen before include "1 & 1 & 1" , "Individuals" , "Singles" , "(Of ship) returning to port of origin" , "Units" .)