The Hollow Ones

There are entities - in the depth of space or other worlds - that are best described as hungry. These beings are filled with a gnawing, all-consuming need to devour, to draw light and life and substance into the sucking void within them.

Thankfully, their very nature restricts them. Everything they contact directly is devoured, and their empty, formless bodies have little way to influence the world.

There are ways, however. By intangibly reaching out, they can forge a connection with thinking beings, hollowing them out within to become an extension of the all-consuming void. The hollow ones are people who have suffered this fate.

Hollow ones come in two forms. Lesser hollow ones are the vast majority, pitiful empty things constantly trying to fill the gap within them. Greater hollow ones are far more unusual. A Wendigo already understands and harnesses their hunger, so when hollowed they can use this to far greater effect. A greater hollow one forms a link to the void much like between a mystic and their patron, drawing on the emptiness to enhance their own power.

A lesser hollow one remains like the character they once were, with a few exceptions.

• They require three times as much food each day to avoid starvation; three full meals worth.
• They heal slowly. They never heal more than a single point of damage from any source of healing (including Medicine rolls, rest, spells, herbalism and so on).
• They are emotionally numb. Any magic that would influence their emotions automatically fails.
• Their unarmed attacks deal normal damage, but also stand a chance of hollowing out the victim. The victim must make a Save against Magic. If they fail, they immediately take d20 damage to their Charisma score. If this damage is enough to kill them, their body crumbles to ash and is utterly destroyed. If they survive, then they are hollowed out and become another hollow one (greater if they are a wendigo, or lesser otherwise).
• If they are a Mystic, then their connection to their patron is devoured and the void becomes their patron. Re-roll all of their spells immediately. The next time they attempt to cast a spell, the Charm roll fails and they must roll on the Fickle Whims of the Divine table automatically.
• If they are a Magician or Morlock, the Void seeps into their minds and infects their ability to cast spells. Whenever, they would suffer Magical Backlash from casting unsafe or experimental spells, they must also roll for the Fickle Whims of the Divine.
• They are infertile. They will never have any children, and cannot be cloned or resurrected. Consuming their flesh gives a wendigo or hollow one no benefit. 
• A hollow one can be easily identified as 'wrong' on casual observation. They are gaunt, pallid and anaemic looking, and are constantly hungry. The precise nature of the problem is not clear unless the observer is already familiar with hollow ones, of course.

A greater hollow one has all the effects of a lesser hollow one, as detailed above. A wendigo can, however, still heal fully by consuming human flesh like normal. Furthermore, whenever they deal charisma damage with their unarmed attacks, their condition progresses further.
Each time their condition progresses, their unarmed damage goes up a dice-size. First d4, then d6, d8, d10, d12 and finally d20.

• After the first progression, the void overtakes their ability to cast spells. From this point on, rather than choosing spells, they pick a spell level and then roll a random spell. They can avoid taking damage when they cast a spell by rolling on the Fickle Whims of the Divine table.
• After the second progression, the hollow one heals fully whenever they hollow out a victim of their unarmed damage, just as if they'd consumed human flesh.
• After the third progression, they can command other hollow ones around them. A lesser hollow one must obey any order given to them by the greater hollow one, much like if the spell Command had been cast. At this point, the void infects their mind fully, slowing their ability to grow; all their XP costs to gain levels are doubled.
• After the fourth progression, the hollow one automatically devours the magic from any magical item they touch. The magic item becomes completely mundane, and the hollow one heals fully just like they'd consumed human flesh.
• After the fourth progression, no save can be made to avoid being hollowed out. A victim who is damaged by the hollow one's unarmed attack takes charisma damage automatically and is hollowed out if they survive.
• After the fifth progression, anybody who touches the hollow one is automatically hollowed themselves. They only take charisma damage if they were attacked.
• After the sixth progression, the hollow one no longer heals by any means (including magic, rest and consuming human flesh). The only exception to this is when they hollow out a person, which heals them fully as before. After this, there is no further progression to the hollow one; they have achieved their maximum potential.

Like Driders and Eloi, becoming a hollow one is another means of sideways progression for the game, at least for Wendigos. Of course, as well as this, an outbreak of hollow ones can become a horrible threat to the local community, so they make excellent monsters too.