The five form The Kurosagi Corpse Delivery Service, specializing in carrying out the last wishes of their dead clients, so their souls can move on.
One of those series that the publisher was releasing was the Kurosagi Corpse Delivery in omnibus form after originally doing singles way back in the early days.
In Japan, the series is up to twenty-five volumes so there’s definitely some space and future materials to work with.
Dark Horse Comics has been involved in manga since nearly the company’s inception back in the 80’s, bringing out works before it was “cool” to do so.