Riku

Riku (リク) was born long ago to the nature-loving and peaceful Linto (リント) Tribe and was chosen to become the Ancient Linto Warrior known as Kuuga (クウガ) to defend them against the battle-hungry Gurongi Tribe (グロンギ族).

Biography
The peaceful Linto Tribe lived their days coexisting with nature. One day, the tribe Shamans predicted a great darkness approaching and chose Riku to become their defender against the Gurongi Tribe, who have gained beast-like powers after their weapons smith made weapons out of the Amadam meteorite.

After Riku defeats every Gurongi attacking his tribe, Daguva confronted him. Riku managed to defeat Daguva with the help of Gouram (in the form of the Horse Armor). He sealed Daguva and the rest of his tribe using his own power and the Amadam's until the year 2000 when a group of archeologists found and disturbed his sarcophagus, which accidentally lifted the seal. Although it was said that his body was destroyed by Daguva, it was revealed by Episode 39 that he was still alive around the time the Gurongi revived.

Kuuga's Forms
The Ancient Linto Kuuga had four base forms that he relied on. His armor, eyes, as well as the Amadam Core on his belt would change color depending on the form. Like the Go-Gurongi, Kuuga can alter any item he has into a weapon by temporarily changing its atomic structure. Only four of his forms were known and recorded by his tribe (that was later deciphered by Sakurako Sawatari) and it is unknown whether he had accessed the Amazing and Ultimate Forms, although it is possible that Riku chose not to use latter forms because of its side effects. It is unknown if he had even a Growing Form, as Zu-Gumun-Ba expressed surprise when the future Kuuga had the white Growing Form.

Equipment

 * Arcle - Kuuga's transformation belt.

Arsenal

 * Dragon Rod - Staff used by Kuuga Dragon Form
 * Pegasus Bowgun - Bowgun used by Kuuga Pegasus Form
 * Titan Sword - Sword used by Kuuga Titan Form
 * Gouram - A mysterious, stag beetle-shaped entity that assists Kuuga.

Trivia

 * Since Yusuke couldn't defeat Daguva without using Ultimate Form, Riku must have used either this form or at least Amazing Mighty Form. Considering that Riku was born into the Linto Tribe and was specifically chosen to become Kuuga, however, it is also likely that with his level of power he could seal all of the Grongi without using Kuuga's full power.