At the end of the hallway you'll enter a room where you'll have to fight Doga, and then Unei. Both are very similar, using powerful Spells against the party each round. Doga favors Breakga, requiring Stona or a Gold Needle to counter it. His Drain and Quake Spells are powerful, but there's no special strategy to avoid them. He resists every Element, so Bio or Mega Flare are your best best for dealing a lot of damage with magic.
Unei uses Tornado quite often, so make sure to heal from it before she decides to use Snowstorm to finish weakend characters off. She can cast Reflect, making Bio a risky Spell to cast. Mega Flare is your best offense, if you have defeated Bahamut and Titan.
Once both fights are won, get the Eureka and Syrcus Keys from the pair, then walk or Teleport out.
Unei uses Tornado quite often, so make sure to heal from it before she decides to use Snowstorm to finish weakend characters off. She can cast Reflect, making Bio a risky Spell to cast. Mega Flare is your best offense, if you have defeated Bahamut and Titan.
Once both fights are won, get the Eureka and Syrcus Keys from the pair, then walk or Teleport out.