You can unlock One-Eye by capturing four of each Eye/Bat-type fiend, which includes each of the following:
- Floating Eye (Mi’ihen Highroad)
- Buer (Thunder Plains)
- Evil Eye (Macalania)
- Ahriman (Mt. Gagazet)
- Floating Death (Omega Ruins)
HP: 150,000
Defeating One-Eye is an important step in the power-leveling process, but One-Eye can be pretty painful to defeat if you’re not prepared. Like most flying and Bat-type enemies, it is tough to hit with standard physical attacks other than from Wakka. It also has an attack called Shockwave, which will inflict several negative status effects, including Confusion, Darkness, Silence, Sleep, and Slow.
As such, you need to make sure that you have a character with the 
Ribbon auto-ability to survive its onslaught.
Alternative strategies that you can use include summoning the Magus Sisters and getting Sandy to use Razzia twice. You can do this by selecting the “Fight” option and then selecting “One more time!”.
You should consider power leveling your characters and obtaining the Celestial Weapons, in this case, for Yuna specifically. Check out the Advanced section of the Tips and Tricks for more information. With properly leveled characters, this fight is pretty straightforward.
| Ability | Description |
|---|---|
| Sensor |
“Immune to sensors.” |
 Scan |
“Immune to scans.” |
Steal:
Lunar Curtain (x3) (common)
Blessed Gem (rare)
Drops:
Magic Def Sphere (common)
Dark Matter (rare)