Devil's new advanced jolly personality (5)
I believe the answer is:
santa
'jolly personality' is the definition.
The definition suggests a singular noun which matches the answer.
'devil's new advanced' is the wordplay.
I cannot really understand how this works, but
'new' could be 'n' (common abbreviation eg NT for New Testament) and 'n' is found within the answer.
'advanced' could be 'a' (abbreviation) and 'a' is present in the answer.
The remaining letters 'sta' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for santa that I've seen before include "patron at Christmas" , "Present bringer" , "Dad in a red and white outfit?" , "generous visitor" , "bringer of gifts" .)