This version of Count Dooku depicts him during the Clone Wars. He trained the sith Asajj Ventress.
Role in Lego
He appears in the video game Lego Star Wars 3: The Clone Wars as one of the three main bosses (the other two being Asajj Ventress and General Grievous). He costs 250,000 studs and can be found in the hanger of the Sith hub.