Gold Craver, as recently discovered, is NOT the son of Lord Beckett. He is a Lucian, and that just makes him more dangerous.
Lucian symbol
The Lucian Branch is one of the five Cahill branches. Lucians are experts at secrecy, sabotage, poison weapons, leadership, and lying. Luke Cahill was the founder of this branch. Many people have blamed him for starting the fatal fire that killed Gideon Cahill, as he had felt, as the oldest, he had not been given a fair share of clues. Evidence of starting the fire was in his diary and given to Jane, his favorite sister, but there is not enough proof to confirm it was him who started the fire. It was, in fact, Damien Vesper who started the fire. The Lucian mascot is a white, double-headed snake wrapped in a slightly complicated pattern around a medieval sword. The heads are located at each end of the snake, where they bare their fangs and tongues and appear to be hissing. The snake represents stealth and sneak attacks (the element of surprise), just like the Lucians favor. The two heads represent that even when you think they aren't looking, Lucians will always know that you're there, and they will always be willing to fight to earn a clue, money, some other object of importance, or just simply to kill you due to a grudge. The sword represents the ruthlessness that the Lucians have the reputation for.
The Lucians are known for their leadership skills, love for poisons, and the endless amount of wealth. They can earn billions of dollars using a simple strategy in one day. Lucians use a special algorithmic code to communicate that is known only to them. This code may be one of the codes in the Agent Handbook. The Lucians even created the Enigma Code during World War II. The Lucians are some of the greatest spies and leaders the world has ever known. They are generally feared as they are known to be ruthless.The Lucians have come the closest to finding all 39 Clues. The Lucians now dominate the world as presidents, kings, world leaders etc. Lucians tend to try to keep their fear of the Madrigals a secret, though. If you are a Lucian and you drink the serum, it is seen (Isabel Kabra) that it makes you extremely ruthless, and will make you almost heartless.