The Red Queen was an AI that appeared in the 'Wonderland' setting of Drake's machine. It is based off the similar character who appears in Lewis Carroll's Alice's Adventures on Wonderland.
After Neku successfully defeated the doormouse, March Hare, and Mad Hatter, Drake sent the Red Queen with her card soldiers to attack him en masse. Drake switched programs before they were able to complete their goal. (Disruptive Selection)