Lyon

She is the partner and younger sister of Annie. Although the younger sister, Oakley appears to be the brains behind the operation. Annie may be more suave, but Oakley is the mastermind of the plan. Unlike Annie, Oakley has a lust for power; Oakley is quick to use the DMA, and once at its helm, her desires for power take over. In the dub, she says, "I can control the whole world from in here!"; in the original, "Now this city is mine!" (もうこの町はあたしのもののよ！).

She only uses it briefly, but Oakley is quick to learn how to use the DMA. In that time, she floods Alto Mare, almost drowns Ash, resurrects Kabutops and Aerodactyl fossils, among other things. Adept as she may be at using it, however, she does not know where to stop, and that eventually proved to be her downfall.

(Source: Bulbapedia)