Lightgazer is possibly the hardest God-Beast to fight early on since he is very strong and has many tricks up to his round self.
First of all his damaging potential is enormous with Geyserblast and Prisioner, which also moogles your entire party. If you try to attack him with Dark spells he'll usually cast Heal Light on itself or Magic Shield.
Another of its tricks is to lower the Attack Power of anyone randomly and without any warning at all not to count he may put Saint Saber on your character which nullifies every and any damage you do to it unless you have used Specter's Eye on it or Stardust Herb on the character.
Unless you have Duran as Gladiator in your party and the item Duelist's Proofs, Duran as Duelist or Carlie as a Necromancer you won't have Dark Saber which would make this fight so much easier.
Characters and classes: Carlie - Priestess [Light] Kevin - Bashkar [Dark] Duran - Gladiator [Dark]