Shun Kazami is one of the calmest Brawlers in the series. He rarely gets flustered or annoyed and even when he is annoyed; he maintains a cool voice (even though he voices his displeasure). Shun is a lone wolf and always focuses in battles. However, his stamina does have its limits; shown by how he tires after a large amount of constant battling. He has distaste for BakuNano as he sees them as dangerous for inexperienced Brawlers to have but gradually uses his own when needed. Shun has good instincts as he is able to discern a person's actions by their personality.
Shun Kazami lives in the province and is a Ventus attribute brawler. He is also an aspiring ninja, receiving training from his grandfather. He is a loner, yet is still willing to help his friends at all costs. Together with Dan Kuso, his best friend and childhood friend, he invented the gameplay for Bakugan. He had been the first ranked battler until Masquerade and his minions dominated the rankings and because his grandfather didn't let him play, ending up in 6th place. After defeating Komba, he ends up fifth. Shun is currently in 3rd place. Marucho and Runo try to convince Shun to join the brawlers, but he defeats both of them in battle. Eventually later he agrees after a situation with Dan and Masquerade. Dan, Shun and the brawlers become friends again.
His mother was really sick and it was when she slipped into a coma that Shun gave up on Bakugan, mainly because his grandfather stated that since he has to take custody of Shun until his mother gets better, he can't play the game anymore and has to concentrate on his training. His grandfather lets him brawl again, though. Shun's mom eventually dies.
Shun once left the brawlers when Dan says they don't need him. Alice tries to persuade him to come back and after brawling Komba, Dan appears and asks for forgiveness to which Shun accepts. This is when he realizes he needs his friends the most. After defeating Komba, Shun takes him as an apprentice to Bakugan and ninja training, but only because Komba was literally on his knees begging to be one.
When everyone was thinking about who was the spy, Shun was the other candidate for the spy alongside Alice. Julie mistook his grandfather for Hal-G, but with a little help from Skyress, the problem was solved. Dan blamed him for not telling them that he came in town, but Alice immediately defended Shun, saying that it's not his fault and that there's no need for him to apologize.
After Dan went to the Doom Dimension, Shun was challenged by Masquerade and decided to go to the Doom Dimension himself with the others.
When he was being tested in the Doom Dimension by the Ventus Lord, Shun had to brawl with the child form of his mother. He almost gave into losing and staying there forever, but Skyress was able to make him realize that he has friends who need him and that he needs them. This caused Skyress to evolve into Storm Skyress. When Dan and Drago were battling to get Drago to evolve, Shun and Storm Skyress were the Brawlers Dan battled last. He was defeated after a close battle and Drago evolved.
He was very shocked when he found out that Alice was Masquerade, but instead of protecting her, he made a comment about how "smart" Masquerade was, which caused Alice to cry and flee back to Russia. It is believed that he did this because he felt angered about the fact that she was Masquerade. After Alice saved Dan and Drago he regained his "friendship" with her and later, he and Skyress helped Alice, Joe and Wavern by distracting Naga so that they can give them more time, but they were easily defeated by the Silent Core. After the battle finished, he released Storm Skyress and all of his other Bakugan.