Sird is a character in the manga who worked with Giovanni on the Sevii Islands to capture Deoxys. Later, she fell from Team Rocket's helicopter after it was taken over by Carr, but she (unlike Orm) survived. She also tried to capture Deoxys by destroying its beam but all the main characters from the adventures and Mewtwo blocked the beam while Deoxys fled. In the Emerald chapter, Archie pointed out that Sird saved Maxie's life. That is why she got fired from Team Rocket because Sird is Team Aqua's #1 enemy and Team Rocket does not want to deal with afflictions from other teams.
Later in the Diamond and Pearl Arc, it is revealed she fought against Riley because Sird was actually a Team Galactic member.