Comes to play fantastic soul in arena (9)
I believe the answer is:
colosseum
'arena' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for colosseum that I've seen before include "Roman landmark" , "Stadium" , "Great amphitheatre in Rome, recently repaired" , "Amphitheatre built in ancient Rome" , "Where some performed" .)