Activision has asked for permission to add EA to a lawsuit Activision filed earlier this year against Jason West and Vince Zampella. West and Zampella were cofounders of Activision's Infinity Ward, one of two studios that produce Call of Duty. The filing seeks $400 million in damages from EA for allegedly interfering with the employment contracts West and Zampella had with Activision, in an effort to sabotage the success of Call of Duty.
West and Zampella formed a new development studio called Respawn Entertainment and that EA will publish its games. They then sued Activision in March, alleging that the games publisher cheated them out of royalties from Call of Duty and wrongfully terminated them. Activision later countersued. A counter-suit is a bit like counter-strike where the biggest guns cost the most.
The new complaint alleges EA undermined Activision because its products haven't performed well in the market. It conspired with West and Zampella to break these contracts, the suit claims.