“A cross-complaint allows defendant to assert claims for affirmative relief against plaintiff, or a codefendant, or someone not yet a party to the action, thus avoiding the necessity of filing separate lawsuits on those claims. Claims against plaintiff can be asserted regardless of subject matter relationship [and may be compulsory if such relationship exists]. Claims against anyone else, however, must relate to the subject matter or transaction alleged in plaintiff’s complaint. A cross-complaint may be filed by the original defendant or by anyone against whom a cross-complaint has been filed. A cross-complaint is treated as an independent action. It is not dependent on plaintiff’s action. The issues raised by the cross-complaint are treated as “completely severable” from the issues raised by the original complaint and answer.”
[California Practice Guide: Civil Procedure Before Trial [citations to primary sources omitted]]
