Guard Captain was the title given to senior members of the guards who served the Eight Legs of Metebelis III. A Guard Captain accompanied the Queen Spider to the village and, speaking for her, demanded that Arak surrender to punishment for attacking Field Guard Draga, otherwise one male from each family would be taken in his place. Sabor claimed to have helped Arak escape to the hills and the Queen ordered the Captain to take him into custody instead. When Neska objected, the Captain had a guard stun her. In the commotion, the Queen noticed Sarah Jane and realised she was a stranger, resulting in the Captain taking her prisoner as well. At that moment, the Third Doctor arrived in the TARDIS and ended up fighting with the guards. After he had overpowered several, the Captain hit him with a psychic blast, apparently killing him. With Sarah having slipped away in the confusion, the party left with Sabor as their only prisoner. The Captain later discovered the Doctor breaking into the spiders' citadel and fired a psychic blast at him but the Doctor deflected it with a machine. The pair grappled and Lupton intervened, ordering a guard to kill the Doctor, but the Captain received instructions to instead arrest Lupton and take him to the spiders' council.
The Second Guard Captain appeared to be the senior of the two, since he ordered the Captain to arrest Lupton on the orders of the Queen. When the Doctor then tried to walk away, the second captain pursued him. The Doctor threw the captain to the ground but was promptly arrested by two guards. The second captain later went to the spiders' larder to fetch Sarah for the queen. When Arak's rebels attacked the citadel, the captain fired a psychic blast at him but it was absorbed by a stone Arak was wearing on his forehead. The captain then fought with Arak while Tuar freed Sabor. (TV: Planet of the Spiders)