Suggested by Destroyer Raikou is a Pokemon of unbelievable power. He is one of the legendaries after all and while that term may not mean a whole lot with some of the fighters, for the most part you can expect a tough fight out of that. Shiron has power ups of his own but I don’t think he would be fast enough to escape Raikou’s attacks or powerful enough to take him out in time. Ultimately Shiron will go down here. Raikou wins.
Suggested by Destroyer Shiron is the main dragon in Legendz and is a pretty strong guy overall. He got several super forms but none of them would be nearly enough to take down Chibi. Dragon Drive has a much higher ceiling when it comes to power levels so when two main characters fight you know how it’s going to go down. Chibi is ultimately better in every single physical stat so it’s hard to get past that. Shiron just doesn’t have the techniques to overcome that. Chibi wins.