The Prince of Yamato Tribe, 'Warrior of Justice'. He was raised believing that the King of the Yamato Tribe was his father, until it turns out he was adopted from the King's sworn enemy, the Black Knight. His natural brother Burai antagonizes him for being raised by their real father's old enemy, but Geki successfully convinced him to bury the hatchet of hate. He wields the Ryugekiken and after Burai's death, he dual wields it with Burai's Zyusouken.
Badass: Throughout the series he does things that make Jason blush.
Law of Chromatic Superiority: His Guardian Beast Tyrannosaurus is the only mecha that can fight giant-sized Dora Monsters by itself and finish them off occasionally (since it's the only bipedal type out of the main five).
A Knight from the Etof Tribe and the Warrior of Courage. A happy-go-lucky jokester guy who's Hotblooded and likes to slack off, though once he set his sight on something noble, he'd never stop pursuing it.
She's Got Legs: About halfway through the series, Mei's skirt in her civilian outfit is exchanged for noticeably shorter shorts. This appears to have been done not for Fanservice, but for practical reasons, as Mei takes a much more active role in the fight sequences after this point.
Tomboy and Girly Girl: Surprisingly, she is the tomboy in her rivalry with Lamie, mostly because of the trope above and several of her so many hairstyles tend to make her look short-haired (she just ties her hair short)
Light Feminine and Dark Feminine: On the other hand, though, she's not a complete tomboy and most of the time doing a LOT of feminine things (like liking flowers).
Burai/Dragon Ranger | Actor: Shiro Izumi
The Warrior of Power from the Yamato Tribe. The elder son of the Black Knight and Geki's estranged brother, who came to resent Geki after he was adopted and raised by their father's enemy, the King of the Yamato Tribe. When he came back, he started antagonizing his brother and the Zyurangers, but eventually lets go of his vengeance and aids him in battle even though he has a limited life. Eventually, Bandora discovered his secret and destroyed his hideout, thus slowly killing him, but not after he passed on most of his strength to Geki.
Knight of Cerebus: His introduction provides an arc that's much more serious than the earlier episodes, and his approaching death provided for some more serious episodes leading up to it.
Redemption Equals Death: Clotho mentions that even though the Zyurangers couldn't save Burai's life, by fulfilling his wish to save the life of a dying boy they could save his soul- possibly, this sacrifice was what allowed him to be forgiven for the evil he'd done in the past.
Jerkass: Despite being a god (or perhaps because of being one) he acts like one on multiple occasions; holding imperfect mortals to his own godly standards and can be especially harsh in dealing out discipline for mistakes and insubordination.
Jerk with a Heart of Gold: Although he IS one of the good guys and fights for the greater good. Nor is he afraid to admit when he was wrong.
Plus in the end, he decided to merely seal Bandora and her followers away rather then kill them.
Jerkass Has a Point: Despite being brothers, as Daizyujin pointed out, Geki's hesitance to kill Burai put both his teammates and innocent civilians in danger.
Mecha Expansion Pack: He can "wear" Dragon Caesar as a helmet and cape to become Zyutei (Beast Emperor) Daizyuzin and then "ride" King Brachion as a steed to become Kyukyoku (Ultimate) Daizyuzin.
Make My Monster Grow: "Evil spirits resting beneath the Earth, grant us now - HAAA! - your powerrrrrrr!". It says something about Bandora that she is the rare Big Bad who is directly responsible for growing the MOTW.