Sickly Lord Byron's only character that descends (6)
I believe the answer is:
sugary
'sickly' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for sugary that I've seen before include "Excessively sentimental" , "Excessively sweet or saccharine" , "Sweet, syrupy" , "Sweet, perhaps too much so" , "Over-sentimental" .)