Gelasia started out as a thief to a little bit of everything, but as her noteriety in non-pokemon communities grew, she found herself feeling limited by what she could steal, alone, without a pokemon.

When rumors of team rocket invading Kodo started drifting to her section of the underworld, she decided solo work was getting boring, and to team up with rocket would be the way to make life interesting again.

She grew up in a wealthy family, spoiled rotten. But this life didn't appeal to her. There was no challenge. As a young teenager there was talk of her getting married off to another high class family. She left, finding an abandoned warehouse to stay at in the docks.

Her opinion is if its not stolen its not worth having. Stealing gives thrill to possessing that she never got in a wealthy family. She reluctantly accepts her team rocket uniform as long as she can steal someone else's uniform later.

She retains her cat burgler mask.