Chibi and his dragon forms are all very powerful but they’re not going to be enough to stop Gray. Gray’s ice abilities are far too much for Chibi to handle. While his fire blasts are powerful, Gray has blocked hits from Natsu. That scales him to a level where Chibi can never hope to reach. The difference in power is just too great at this point and Gray won’t be able to keep up. Gray (Fairy Tail) wins.