Last character with energy very much a fanatic (6)
I believe the answer is:
zealot
'a fanatic' is the definition.
(thesaurus)
'last character with energy very much' is the wordplay.
'last character' becomes 'z'.
'with' is a charade indicator (letters next to each other).
'energy' becomes 'e' (physics symbol as in E=mc2).
'very much' becomes 'alot' ('a lot' can be a synonym of 'very much').
'z'+'e'+'alot'='ZEALOT'
(Other definitions for zealot that I've seen before include "Fanatic person, much too enthusiastic" , "Fanatical adherent" , "Fervent enthusiast" , "Fervent partisan" , "Fanatic or extreme enthusiast" .)