Normal: "A fiend that appears to be a machina, but is actually an empty suit of armor animated by pyreflies. It's quite strong, but it relies far too heavily on sight." Oversoul: "One angry suit of armor. Something must have happened when it oversouled, because now it focuses all of its attention on attacking White Mages." — Scan
The Gemini is an enemy in Final Fantasy X-2. Gemini is one of the constellations of the Zodiac, and as such, its sword's cross-section is a six-pointed star. It always comes in pairs, and is a rather difficult enemy to face due to high stats. It is best to hit them with Armor Break and Power Break to lessen the damage inflicted by Gemini, and increase the damage dealt to the enemy. Casting Protect at the start of the fight is a smart idea, and using any magic on them will be effective as well if the player uses Mental Break.
When Oversouled, having elemental resistant equipment and access to Reflect and Shell helps protect against their elemental attacks.