Darkstar is dark gray tom with cold, ice-blue eyes. He is self-centered, short-tempered and selfish.
He forcefully made Midnightcrow his mate. They've had many kits together. Branchscratch, Birdfeather and Mistpaw are the only living ones, the others have died. Darkstar wants to have more kits. Midnightcrow resents him.
Later on, Darknesskit plays with Darkstar, but a little roughly. Darkstar has to fight to control his anger, because he knows no one would forgive him if he hurt a kit; he would be driven out of the very Clan he created.
Midnightcrow later comes and tells him she is expecting kits. Though he doesn't know it, the kits are really one of his warriors, Lynxclaw's, who Midnightcrow has been meeting behind his back. He is worried about her welfare, and his kits due to the loss of other kits born to him.
When the kits sneak out of the camp, he tries hard to control his anger, as they caused the death of Hazelkit and Vixenpaw to a fox.
He makes Mistpaw, Foxpaw and Kinkpaw warriors (Mistrain, Foxtail and Kinkfeather), and Runningkit, Ashkit and Brookkit apprentices. He appoints Boneleap as temporary deputy while Midnightcrow is in the nursery.
Darkstar and Midnightcrow get into more heated arguments, Midnightcrow is mad at him confining her to the camp, though she sneaks out several times for reasons unknown to Darkstar. One day Midnightcrow sneaks out of camp, and Darkstar follows her scent trail. He discovers her kits were born, and that they were not truly his, but Lynxclaw's. In his anger, he kills Lynxclaw and exiles Midnightcrow and her kits. He tells the Clan that they were spying on SharpClan for another clan, and Lynxclaw had been hit by a monster on the Thunderpath, while Midnightcrow had escaped. He warns the Clan to be on their guard.
"The clan leader's word is law, you broke the warrior code." --Darkstar to Midnightcrow before he kills Lynxclaw.
"It pains me to say this, but Midnightcrow and Lynxclaw have been spying on us for another clan! They are traitors! I chased them over the Thunderpath, and Lynxclaw got hit. Midnightcrow escaped, and is no doubt plotting against us. Any news of her should be reported" -- Darkstar's lie to SharpClan about Midnightcrow's exile