Fafnir is covered with hard scales, meaning weapons without the Piercing ability do little damage. It will use his physical attack on the party member with the lowest current HP. Fafnir's Triple Attack is powerful, and its first physical hit is unaffected by Protect, though the damage from its final hit is reduced by it. Triple Attack is a physical attack followed by an elemental attack on the whole party, and finishing off with another physical. The final attack will not come if two characters are KO'd by the second.
Fafnir's physical attack can break the damage limit when used on its own, but not when used as part of Triple Attack. Fafnir's fire-elemental breath can break the damage limit, but its ice and lightning ones cannot.
Element Eater armor will make Fafnir less likely to kill the party. If they are not used, then NulBlaze, NulShock, and NulFrost should be maintained (NulTide is not needed), and in such a case it is important to keep everybody alive, as a newly-revived character would need three Nul-spells cast on them. Rikku's Hyper NulAll Overdrive mix is especially useful in keeping each Nul-spell on.
In addition to Protect, Cheer may make the difference between a character surviving and falling when they're the primary target of Triple Attack. The party should be in Haste, especially since Fafnir can use Triple Attack frequently.
Alternatively, this can be an easy fight if one has well-upgraded aeons. Ifrit or Ixion are best suited since one in three of the elemental attacks will heal them rather than harm them (Shiva absorbs ice but has lower HP). Using Haste and maintaining Nul-spells for the other two elements will negate all the breath weapons. Ideally, Auron should use Banishing Blade to 100% Armor Break before Yuna summons the aeon. Normally Armor Break only works 5% of the time against Fafnir but a Frag Grenade or Banishing Blade always work.
Fáfnir (Old Norse and Icelandic) or Frænir was a son of the dwarf king Hreidmar and brother of Regin and Ótr. Fáfnir was a dwarf gifted with a powerful arm and fearless soul. He guarded his father's house of glittering gold and flashing gems. He was the strongest and most aggressive of the three brothers. Fáfnir eventually killed Hreidmar to get all the gold for himself. He became ill-natured and greedy, so he went out into the wilderness to keep his fortune, eventually turning into a serpent or dragon (symbol of greed) to guard his treasure.In Norse mythology,