For example, when it uses its Fire-type move Flame Charge in battle, in addition to doing damage, Fletchling's Speed increases every time. Although it is known to be very friendly, Fletchling will suddenly unleash relentless attacks once it's in battle.
This is the first new type since Dark and Steel were introduced almost a decade ago. Unlike any other Pokémon region there's one central location which you'll be passing through a lot, Lumiose City.