Special Executive

The Special Executive (conversationally contracted as Special Exec) were a mercenary group of parahuman lifeforms, led by Wardog. They worked across time and the multiverse.

They were hired by Gallifrey in the early days of the Time Lords to retrieve the assassin Fenris. Wardog, alongside Time Lady Rema-Du, did the retrieval, and Viridian the Brainfeeler scanned Fenris' mind to identify his employers as the Order of the Black Sun. At that moment, agents of the Order attacked; Viridian was killed and Wardog had his left arm blown off. (COMIC: 4-D War)

Ten years later, the Executive — Wardog, Zeitgeist, Cobweb and Millenium — escorted Rema-Du to a trade negotiation that involved the Sontarans and a third party. The third party turned out to be the Order from before they declared war on Gallifrey. The Sontaran ambassador brainwashed Millenium with a psy-snare and had her murder the Black Sun representative. Wardog killed her in a failed attempt to stop the murder — and because the Executive were employed by the Time Lords, the Order of the Black Sun believed this to be a deliberate assault and declared war. (COMIC: Black Sun Rising)

Behind the scenes
Alan Moore, their creator, did not write any further Doctor Who strips, preventing him from using most of the material he had planned for the Executive. He went on to use them in the Captain Britain strip of Marvel UK's The Daredevils — one of multiple crossovers between Marvel Comics and Doctor Who by the UK branch. They made two subsequent cameos after Alan Moore finished writing Captain Britain, one in Captain Britain Monthly, and one in Marvel's Excalibur, the former showing that Wardog was the second leader of the Executive.