Hastur explains that Ashbless is in fact eight hundred years old, initially one of the Knights Hospitaller during the Crusades, but entered a devil's bargain: Ashbless owns Hastur's soul, and is immortal so long as he has it. Should Ashbless give up or lose Hastur's soul (represented by a talisman stylised as an eye—a symbol seen throughout the ship), Hastur would be free to exact revenge upon Ashbless' soul.
Hastur reveals that Ashbless is eight hundred years old, having been a Knight Hospitaller during the Crusades. He made a deal with a devil, giving his soul in exchange for immortality. If Ashbless releases or loses Hastur's soul (represented by an eye-shaped talisman), Hastur will be free to harm him.