Ultraman Gaia, the third Heisei entry in the Ultra Series, came out in 1998 and ran for a total of 51 episodes. Gaia tells the story of Gamu Takayama, a student who unites with the eponymous Ultraman and fights against aliens and his mysterious rival, Ultraman Agul.
Gaia is notable for being the brainchild of prolific anime writer Chiaki J. Konaka, known for his work on Digimon Tamers and Serial Experiments Lain. His brother is director Kazuya Konaka, who worked on Ultraman Nexus.
The Crunchyroll synopsis reads:
At the dawn of the 21st century, the Earth faces destruction. Its savior turns out to be super- intelligent college student Gamu Takayama, who bonds with the mysterious light of Ultraman Gaia in order to stop devastating attacks by inscrutable aliens. Gaia receives the support of Earth defense organization X.I.G., but soon finds himself clashing with another mysterious giant, Ultraman Agul, who thinks protecting the Earth doesn’t necessarily mean protecting humans.
All 51 episodes are now available to Crunchyroll members everywhere expect Asia. Watch Here.