Ending 1 - Agree with Glen, win battles, defeat Gulos by destroying all statues and his
Ending 2 - Refuse Glen, win the battle and defeat Gulos by destroying only 1 statue / Agree with Glen, win the battle, go and break the statue alone and defeat Gulos by destroying only 1 statue
Ending 3 - Refuse Glen, lose battles and defeat Aifolen
Ending 4 - Try to escape
Ending 5 - Agree with Glen, win the battle, defeat the statues/Gulos
Ending 6 - Refuse Glen, win the battle and defeat in front of the statue or Gulos himself / Agree with Glen, win the battle, go and break the statue alone and defeat in front of the statue or yourself Gulos
Ending 7 - Refusing Glen, losing in battles and losing to Aifolen
As for losing or winning in arena battles, I can't say for sure how they can affect the outcome. But at least if you do it as I wrote - the endings will be correct
My English is bad, but I hope you understand what I translated with the help of a translator.