Kenneth Crichton was next in line to take on the identity of Union Jack, but refused, stating that his friend Joey Chapman was better suited to be the new Union Jack. Joey agreed and became Union Jack. Suffering from anemia and feeling estranged from Joey as Union Jack and his recently rejuvenated mother, Lady Crichton, Kenneth became an easy target for Baroness Blood, who turned him into the new Baron Blood as a "cure" for his anemia. The Baroness used Kenneth and several other vampires to obtain the Holy Grail, which gave her immunity to sunlight and the other traditional weaknesses vampires had, but she didn't want to share this power with other vampires and destroyed the Grail. The sun rose and Kenneth and the other vampires all died, despite Union Jack's efforts to save Kenneth.
As a vampire, Ken possessed enhanced strength (lifting 2 tons), speed and agility. He could mesmerize with a glance, turn into mist or a bat, did not age and regenerated from injuries.
He was vulnerable to garlic, sunlight, silver and holy water, needed to drink blood to survive and to sleep on a layer of his native soil, and could be destroyed by a wooden stake through the heart.