The Soul Catcher was used originally by Necromancers to trap and destroy souls until they banned the process for being too cruel.
Before Skulduggery was rescued by Valkyrie, Billy-Ray Sanguine stole the Soul Catcher from the Temple as part of the Revengers' Club's plan. It was not realised until Skulduggery points this out. With the Soul Catcher, and the help of the Zombie Horde, Sanguine captures a Remnant. The Remnant is used to possess Kenspeckle Grouse so he would repair the Desolation Engine, and make a copy.
Valkyrie, Anton Shudder, Skulduggery and Ghastly manage to get into the Revengers' Club's base (Serpine's castle), and rescue Grouse. With the help of China Sorrows, the Remnant is forced back into the Soul Catcher. The High Priest, Auron Tenebrae, tells Solomon Wreath to take back the Soul Catcher with the Remnant still in it.
With the Remnant in the Soul Catcher, Auron tells Wreath to possess Finbar Wrong, a Sensitive, so they could tell if Valkyrie is the Death Bringer. However, the plan goes wrong and the Remnant escapes. The Soul Catcher is presumably back in the Necromancer Temple.
After The Irish Sanctuary stormed the Temple, it was presumably abandoned.