The text says, "The 9th Hero... Violet created the Zyuden Arms!"
Speculation was running high that Pleseon was going to have a hero associated with him, and that turned out to be true. If you're curious why the Gaburevolvers all have Shigeru Chiba's voice, and why the Spirit Warriors don't use the Gaburevolvers to transform, there's an in-universe explanation. Shigeru Chiba will be playing Dr. Ulshade, a genius scientist and a retired Kyoryuger, Kyoryu Violet, who just happens to be the one who developed the Gaburevolvers (and in fact, numerous weapons based upon the Beast Batteries). With upcoming upgrades for Kyoryu Red and possibly the others, could Dr. Ulshade be the one who'll develop them? The answer is, yes, probably.