Zogu

Zogu, also referred to as Angel Zogu, is the final antagonist of Ultraman Gaia. She is an agent of the Radical Destruction Bringer sent to defeat Ultraman Gaia and Ultraman Agul and finally destroy humanity.

History
Zogu came down to Earth with her Dobishi with the intention of deceiving the Ultras. She had her Dobishi merge into Kaiser Dobishi and fight the two Ultras. She then destroyed the Dobishi and healed the Ultras back to full power.

However, Zogu did not keep up her masquerade for long. Soon after, Zogu incapacitated Gaia and Agul and stole their life energy before having her Dobishi army spread darkness across Earth's sky. With the Earth cloaked in darkness, humanity lost their will to fight against the Radical Destruction Bringer.

However, XIG converted the energy of Earth's kaiju into light energy, allowing Gamu and Hiroya to transform into Gaia and Agul once again. Powered up, the two Ultras were able to initially overpower Zogu. In response, Zogu assumed her true form, a bird-like demon.

Now in her most powerful form, Zogu was able beat down both Ultras. Unfortunately for her, she did not hold the advantage for long, and she was destroyed when Gaia and Agul combined and fired their Proton Streams at her, destroying the demonic creature.