The protagonist of the story. He's the red Sword Eyes of Light and Darkness. Tsurugi was taken away from his home of Atlantia when he was little, and was raised in Pacifice. After he met Bringer, he learned Battle Spirits, and decided to go on a quest to meet his mother, and defeat his older brother Yaiba, the current King of Atlantia.
Audience Surrogate: He doesn't know the rules of Battle Spirits at first, thus giving the show an excuse to teach the new viewers how to play.
The blue Sword Eyes of Light. Sora is a mechanic from Atlantia, who lives with his younger brother, Long. He dislikes the royals. Sora is a huge advocate of love, and tends to rant about it during battles.
The yellow Sword Eyes of Light. She's president of the Sweetsmates, an orginaztion devoted to sweet foods. Kizakura comes from a very poor background. She used to live on the streets, until she met her friends Yamabuki and Kogane.
The green Sword Eyes of Light. Hagakure is a ninja from Kolga village, just outside of Lemurion. His dream is to get the Sword of Judgment, so he can become a higher ranking ninja without having to work at it.
Money Fetish: He'll use anything as an opportunity to make money.
Refusal of the Call: He tries this, going as far as using special glasses to hide the fact that he is a Sword Eyes.
Tsundere: He's a Type A, with a crush on Kizakura, and even voiced by Rie Kugimiya. He also plays this role in a platonic way with the other Sword Eyes of Light, trying really hard to not be friends with them.
The white Sword Eyes of Darkness. Yaiba is Tsurugi's older brother, and the king of Atlantia. Though initially portrayed as a villain, Yaiba actually learned as a child that the world would be destroyed by God. He has been secretly acting to save everyone.
A God Am I: He actually wants to surpass God. With somewhat justifiable reason. He plans to kill God with the Sword of Judgment and guide the humans in a world that they run.
Dark Is Evil: He leads the Sword Eyes of Darkness, runs a harsh regime and freely occupies other nations with his armies of Mecha-Mooks.
Dark Is Not Evil: In truth, he plans to liberate humanity by killing God with the Sword of Judgment.
The Evil Prince: He appears this way at first, when he has his mother arrested as a suspect for rebellion, thus taking the throne for himself. Then, well, he's king for the rest of the series.
Villain with Good Publicity: While some people hate the way things are under Yaiba's rule, many love him, and he makes sure to give regular speeches about how he's doing everything in the best interests of the people. The Sword Eyes of Light are even made into wanted criminals.
Then, this is subverted when it's revealed that Yaiba actually is doing everything for the safety of the world.
Well-Intentioned Extremist: Oh boy. Everything he's done is to save the world from destruction and better the people. He just hasn't picked the best ways to go about this. Enough that the Sword Eyes of Light believed him to be evil for much of the series.
Defeat Means Friendship: Subverted. After Tsurugi defeats him, it looks like Gordy is going to join up with the good side. However, Yaiba interferes, and the next time Gordy is seen, he's back to his old self. It works the second time, though.
Disguised in Drag: When he sneaks around to find information on Garudos. He does not pull it off as well as Haqua.
The mother of Tsurugi and Yaiba. After Yaiba took power, her whereabouts were unknown. She is actually involved with the Red Army, and has been waiting for the Sword Eyes of Light to be gathered, so they can stop the shadow figure.
Absurdly Youthful Mother: Aesthetically, considering she has an adult child (who also looks younger than he is.) Unlike a certain other character there's not even an explanation as to why she looks the same as she did 14 years ago.
Damsel in Distress: Subverted. They make you think so at first, but she's actually revealed to be on Yaiba's side, and then later revealed to be a reverse mole.
Expy: Most likely one to Gilfam in Brave. Both are queens. Both have a close female protector with whom they get Les Yay subtext. Both have magical powers. Both are voiced by Michiko Neya.