Paul Barron was a scientist who built a chaos engine capable of drawing energy from a hell dimension through an interdimensional rift, presenting it at the 1933 World Fair in Chicago. However, Barron was rejected and treated as a crazy man both by his peers and the regular public, his pain and obsession led him to become corrupted and influenced by the Old Ones dwelling on the other side.
Under their influence, Barron sacrificed his lover, Bridget, which allowed an Old One to emerge. Spike and Drusilla pretended to feign allegiance to the Old One so it would aid them against the brothers of Xin Rong. After emerging victorious, Drusilla killed the Old One and turned Barron into a vampire.