Although they are known today as the Angels of the Second World, the Slayers were originally mere agents of change, eliminating plants and animals that had outlived their purpose to make way for new, better generations. The Lore of Death granted them the power to end life quickly and painlessly, then render the bodies of the dead back into their constituent particles for the earth to absorb and begin anew. Of all the Houses, the Halaku were forced to evolve the most in the wake of the Fall. With the loss of mankind's immortality, the Slayers were thrust into a difficult and painful situation of ending human life, often well before its time, then surrendering the spirit to an unknown fate. The Lore of the Spirit grew from the desire to prevent the loss of these souls, anchoring them to places on the earth in their former bodies, but this was not enough to protect ghosts from the depredations of loyalist Reapers. Finally, the Halaku decided on a more desperate course; the construction of a haven outside the physical universe where God's Reapers could not find the souls of the dead. The first step in this plan was to learn the ways of stabilizing and traveling to pockets of reality that existed outside the physical cosmos, leading to the evolution of the Lore of the Realms and culminating in the creation of the spirit realm.