Cobb (The Doctor's Daughter)

Cobb was a general encountered by the Tenth Doctor, Donna and later Martha on the planet Messaline. He commanded Cline and the Doctor's daughter, Jenny. Donna called him "Captain Nutjob" after he had her and her friends arrested and spoke of a desire for genocide against the Hath.

Biography
When Cline captured the Doctor and Donna, he took them to see Cobb, who assumed they, along with Jenny, were pacifists from the Eastern Zone.

Cobb asked the Doctor to join his army in the war against the alien Hath. He sought the Source. He believed the Source would give him the power to kill every Hath on the planet. When the Doctor refused to help and instead spoke of stopping him, Cobb had the Doctor, Donna and Jenny arrested for not supporting him in the war. Cobb later found Cline tied up on the floor of the cell, discovering that the three of them had broken out. Cline said Jenny had tricked him.

Cobb and his soldiers chased the Doctor, Donna and Jenny into secret passageways uncovered by the Doctor. When Jenny tried to buy them time by holding up the soldiers, she hesitated to kill Cobb. He tried to convince her to join his cause, stating that it was "in [her] blood". Jenny was already loyal to her father, the Doctor, and he had told her there was always a choice in killing someone. Instead, she hit a pipe to delay Cobb and his troops. When the Doctor told Cobb that if the Source was a weapon he'd never let him have it, Cobb threatened to kill him.

The Doctor, Donna and Jenny were reunited with Martha and found the Source first. They discovered it was a terraforming device. The Doctor declared the war over and released the terraforming device. Cobb blamed the Doctor for ruining his chance at victory and tried to shoot him. Jenny stood in the way to protect her father so Cobb shot her. She was shot through one of her hearts and temporarily killed. The Doctor held a gun to Cobb's head and contemplated killing him, then stopped, telling Cobb that "[he] never would" and that it was on that basis that the new society of human and Hath should he founded. Cobb was demoted, arrested and imprisoned for Jenny's murder. (TV: The Doctor's Daughter)

Personality
Cobb was a vicious, xenophobic and desperate soldier who detested the Hath. He was a hypocrite who claimed that he wanted to restore peace to Messaline, when all he really wanted was to destroy the Hath, as shown when he told the Doctor that he wanted the war won rather than over. He was a tough soldier who was very hard to intimidate, as shown when he casually brushed off the Doctor's threat to interfere with his plan, merely considering it ironic that he was the one who had shown them the way. He took pride in Jenny at first, wishing he had more soldiers like him in his squad. However, he nonetheless locked her up with the Doctor and Donna as he believed she was of "pacifist stock" and couldn't be trusted. After being denied his murder of the Hath, he showed a vengeful side when he attempted to kill the Doctor, but only temporarily killed Jenny instead. (TV: The Doctor's Daughter)

Behind the scenes

 * Russell T Davies suggested in the podcast for the episode that, as well as creating a child from a parent, the machines could clone important figures. General Cobb could be the fifth Cobb of that week.