The Triskele were a race of dolphin-like humanoids; originally barbarians, but later peaceful.
Biology
The Triskele had a humanoid appearance and somewhat resembled dolphins. The Uncreators possessed an extraordinary defence mechanism; for every one of their kind that was killed, three more would arise in their place. Being mindless beasts clouded by emotion and gut instinct, the Uncreators were easily frightened by something they deemed more ferocious than themselves. (BFA: Storm Warning)
History
The Triskele pillaged and plundered the cosmos for aeons until they eventually decided to mend their ways by dividing themselves into three parts; the head, the heart and that which mediates between the two. Thus was born the Engineers, (the rational, thinking side of the race) the Uncreators (the impulsive, brutish side of their species who acted on raw instinct) and the Lawgiver (the embodiment of wisdom and free will who mediated between the head and the heart and decides what it is right to be done). There was only one Lawgiver at any one time.
In the winter of 1929, a Triskele spacecraft containing the Engineer Prime crash-landed in Great Britain, where it was recovered by military forces. Despite believing it at first to be the result of some foreign experiment, Lord Tamworth, Minister of The Air, soon discovered the truth about the alien visitor. By enlisting the help of the legitimate psychic, Madame Zelda, he was able to communicate with the creature and arrange a rendezvous with it's people in the following October. Constructing the R101 to accomplish this goal, he was able to negotiate the safe return of their ambassador in the hopes of being rewarded with some of their advanced technology and weaponry, allowing Great Britain to topple any force that may stand against it. Along with his subordinate, Lieutenant-Colonel Frayling and a mysterious intruder, Tamworth became a representative for one of The Triskelion but after the Lawgiver was accidentally shot, the Uncreators were able to break free and wreak havoc, using the German spy Rathbone as their medium. Rebelling against their control, Rathbone shot the Uncreator Prime, with Frayling becoming the new Lawgiver. Tamworth decided against taking the ship back to England and instead stayed on-board to assist in rebuilding the Triskele and their society in the wake of the catastrophe. With everything back to the way it was, the Doctor and his new companion, Charlotte Pollard fled on their newly found pet Vortisaur, Ramsey, who took them back to the TARDIS while the R101 crashed into the hillside and perished as history intended. (BFA: Storm Warning)