They are granted to characters who used to be alive, and thus characters reanimated as Hollow Ones keep all of the stats of their old race (including new subraces like the Pallid Elf!), and get some traits as well. The Hollow Ones are less of a race and more of a supernatural gift.
Few of these beings become adventurers, questing for vengeance, longing for somewhere else, or a reason to live. Their past weighs on them like a heavy, tattered cloth… Or a sword through the gut. They appear undead, magic recognizes them as undead, and their posture is like that of one already dead. That creates a Hollow One, beings that are seen as normal on the Blightshore, but elsewhere might fall into trouble. Their bodies are souless, departed for the afterlife… And yet, their bodies have a small fragment of themselves, clinging for life. The Hollow ones are beings that were reanimated from the horrendous curses of the Blightshore.
Where were my barely-alive boys? With the Hollow Ones, not only do we get a splash of that undead flavor, but we also get the chance to bring back favorite characters that we weren’t quite done with.
As someone who played a lot of older editions, the lack of any flavor of Undead was a little disheartening.
