Cruz was Bea's daughter. They were apparently close, as Bea mourned reports of Cruz's croaking, and later her apparent turning.
Upon discovering the truth of Decryption however, Bea was horrified. After learning of her daughter's newfound devotion to Toolism and support of Gobwin Knob's crusade, she determined that the decrypted Princess Cruz was not her daughter, but a twisted mockery, and ordered her destruction. She proceeded to do everything in her power to deny any more bodies for the Arkenpliers.