While Zinnia was dealing with Courtney of Team Magma, Aster appeared and followed Zinnia. Zinnia fled on Salamence, while Courtney was halted by Maxie.
Aster was seen with its trainer, Zinnia, at the top of the Sky Pillar. When Ruby also came to the top, Zinnia attacked him. Aster was attracted to the sour Pokéblocks that Ruby dropped on purpose. Zinnia tried to stop Aster from eating it but Ruby grabbed her and pulled her down. After Ruby's battle against Zinnia was over, Zinnia flew on her Salamence with Aster away.
Three Draconids faced Ruby, who exited the Sky Pillar. They told Aster was their real lorekeeper, which made Ruby think they spoke about Zinnia's Whismur. However, they explained Aster was actually a human, who was also a Draconid that passed away, leaving Zinnia as her successor.
Zinnia came to Sea Mauville, where she, as well as Team Aqua and Magma grunts, had routed Mr. Stone's plan to stop the meteorite. Aster snatched Mr. Stone's Dimensional Shifter, though was stopped by a Plusle and a Minun, who gave the Dimensional Shifter to Sapphire. Just before the rocket launch at Mossdeep Research Center, Sapphire sensed Zinnia was nearby, while Steven remembered she came to Sea Mauville with Aster, Team Aqua and Magma grunts to foil their plan.
Aster was with Zinnia, who watched as Ruby and Sapphire flew in outer space with Rayquaza to blast the meteorite and descended down on the planet.
None of Aster's moves are known.