D&D homebrew Planescape

Planescape Threats: The Relentless

One of the best things about Planescape is the setting and style lends itself to experimentation being more readily accepted. People just get less fussed about weird rules, magic items, systems, etc. due to the nature of the game itself. One of the areas where some experimentation and expansion could be used are the exhaustion and inspiration systems. I am a big fan of both, but I am not unaware of the their biggest flaw: the lack of integration into other parts of the game. There are myriad areas where the integration could occur, but doing a full bolt-on theme has been appealing to me for a while. That way, if something doesn’t pan out it can easily be phased out without too much effort or redesigning the current game, and can be expanded if it is successful. It’s a backdoor pilot, essentially. Hopefully without all the awkwardness that is associated with a backdoor pilot. It doesn’t take up an entire episode of a show you were expecting to see, so there’s that. Regardless, let’s spend some time discussing the Relentless – a group of creatures for use in the Planescape setting.

The Relentless – Concept

The Relentless are not a single type of creature, or even necessarily a single cohesive group of creatures. Instead, the moniker refers to creatures who are able to harness the power of the Astral plane to keep their physical forms in motion without the need for rest or recovery due to exertion. The Relentless take this energy from others, using it to enhance and empower their physical forms and the items they have created to support their altered states. The Relentless are able to manifest a portion of themselves through their attacks –  causing a parasitic version of themselves to latch onto their prey either mentally or physically. In the case of the Relentless, the two are one and the same. . The Relentless often form clans or groups with others they encounter who are like them, but there are those who eschew the assistance of their kin, and seek power on their own. Many Relentless consider themselves blessed or chosen by the Astral plane, and carve out domains within it – seeking to become rulers or champions of the Astral. Relentless are fearsome to behold, and none would actively seek them as a foe. They never rest – as their name implies – and their strength comes at the cost of those who oppose them. They are to be avoided at cost, and treated carefully if they must be dealt with.

Exhaustion and the Relentless

The Relentless must feed regularly in order to maintain their gifts from the Astral plane. Relentless still accumulate exhaustion, but are able to ignore it as long as they have fed recently. Recently depends on the strength of the Relentless, who need to feed more frequently the newer and less powerful they are. The longer the Relentless goes without feeding, the more the exhaustion is able to take hold of them.

  • Feeding confers at least one level of exhaustion on a target, though as Relentless get more powerful they must inflict more levels of exhaustion to stay fed
  • Exhaustion powers Relentless abilities
  • Relentless need to feed every day, week, month, or season. If they don’t feed, any existing exhaustion levels they have accumulated now affect them
  • For every 8 hours past the feeding threshold the Relentless goes without feeding, the Relentless gains a level of exhaustion.
  • While fed, the Relentless is immune to exhaustion (any existing levels remain until cured)
  • The Relentless may suppress the ill-effect of exhaustion for short periods of time to try and hunt – scaling based on how powerful the Relentless is
  • Relentless ability are not impacted by exhaustion

Astral Parasites

The Relentless have become warped by their experiences – some say blessed – and have learned to feed upon the energy of others. Each Relentless may do so by either infecting the blood of a victim – usually through claws or bites – or through their thoughts and  dreams. There seems to be no medical difference other than method of contraction. A psychic connection between the infected and the Relentless is formed, allowing the Relentless to feed upon the victim at a distance – though proximity makes it easier and more effective to do so. The infected are conferred some measure of protection from the Relentless. From a physical perspective, the parasite appears to be tiny snails with black shells that shimmer under light. From a mental perspective, the parasite always manifests as a version of the Relentless who infected the victim.

Contracting Astral Parasites:

  • Infection can occur through psychic energy attacks or physical attacks – depending on the Relentless. One Relentless may be able to do both.
  • You must make a Charisma DC 11 + your current exhaustion level saving throw – increasing based on the strength of the Relentless – or contract the Astral Parasite
  • Symptoms manifest during the next short or long rest the infected undergoes (Relentless abilities might immediately trigger the disease)
  • Possessing Inspiration gives you advantage on saving throws against this disease
  • You may spend Inspiration to instantly pass a saving throw against this disease
  • While you have this disease, you cannot contract it from another source


  • Dark circles under the eyes
  • Clammy, bruised-looking skin,
  • Faint, undecipherable singing while asleep.
  • You emit purple light as if you were carrying a candle from any exposed skin


  • During a long you must make a DC 11 – increasing by 1 for each level of exhaustion you currently possess, and varying based on the strength of the Relentless – Charisma saving throw or be able to be fed upon.
  • If you fail a saving throw, you are not able to remove a level of exhaustion during the long rest and you gain one level of exhaustion
  • Possessing Inspiration gives you advantage on saving throws against this disease
  • You may spend Inspiration to instantly pass a saving throw against this disease

Curing Astral Parasites

  • Passing a saving throw against the disease, making a successful Wisdom (Medicine) ability check against the current DC of the disease, or being targeted with a spell or effect that cures a disease does not cure the disease – but it prevents you from being able to be fed upon until your next long rest and allows you to remove an exhaustion level
  • Killing the Relentless who infected you cures the disease
  • Resurrection cures the disease
  • Finding a way to venture into your mind to battle and defeat the parasite will cure the disease

Lingering Effects

  • You have advantage on saving throws against exhaustion that are not caused by the Relentless or as part of this disease
  • You have resistant against psychic damage from sources that are not the Relentless as part of this disease
  • You are resistant to bludgeoning, piercing, and slashing resistance from adamantine weapons
  • Silver weapons will ignore any damage resistance against bludgeoning, piercing, and slashing that you currently possess
  • Being struck by silver causes you to take an additional 1d6 radiant damage for each level of exhaustion you currently possess

Active Effects

  • Astral Parasites go on initiative 10 if their progenitor is not present in the fight, or initiative 20 if it is.
  • If not directed by the progenitor, the Astral Parasites will work to keep you safe.
  • The Astral Parasites grant you a reaction: when you suffer damage from any source other than a Relentless, you may spend your reaction to decrease the damage by 1d6 + an additional 1d6 per level of exhaustion you currently possess. This refreshes on the Astral Parasites turn.
  • If you are currently at or below half of your maximum hit points, the Astral Parasites will attempt to banish you to the Astral plane. You must success on a Wisdom saving throw equal to the current DC of the disease or be sent to the Astral Plane. You may make a new save at the beginning of each of your turns to return. You must continue to do so until you are no longer at or below half of your maximum hit points.
  • The Relentless will seek to act through the Astral Parasites, if it is present.

Relentless Abilities and Traits

The Relentless do not care for silver. Silver bypasses their damage resistance against bludgeoning, piercing and slashing damage. Relentless are immune to psychic damage, sleep, paralysis, and being restrained. They are immune to the effects of exhaustion while fed. Relentless ignore difficult terrain, and are immune to having their movement speed reduced below its base.

While the individual abilities of the Relentless may vary, there are some abilities shared across them.

  • Astral Song: targets creatures within an area around the Relentless, DC 13 (Scaling based on the power of the Relentless) Intelligent saving throw, deals psychic damage and causes a level of exhaustion. This deals additional damage based on the currently exhaustion level of the Relentless.
  • Mind Lash: target one creature, deals psychic damage and allows the Relentless to deal additional damage as a bonus action. This requires concentration. This can transmit Astral Parasites. Additional exhaustion levels let you pick additional targets.
  • Hungry Maw: a bite that deals high damage, transmits Astral Parasites, and allows the Relentless to feed and cure exhaustion levels.
  • Tearing Claws: a claw attack dealing medium damage, transmits Astral Parasites, can paralyze
  • Control Astral Parasites: any victim suffering from Astral Parasites transmitted by the Relentless must fight against the Relentless controlling the Parasites and attempting to feed on them, force them to behave in a certain way, or have them act as if they were affected by bane

Relentless Equipment

It is important that any equipment associated with the Relentless be recognizable. It should have a certain style and flair that makes it obvious to someone investigating it. It should also have material and ability consistencies that speak to the Relentless, as well.

Weapons and armor are made from either iron or adamantite. They tend to be more industrial in design. It should have an almost dirty look to it, even when it is brand new and cleaned meticulously. As far as imagery goes, it should have a cosmic design with a lot of eyes, mouths, things cowering, and symbols that convey strength and stamina when read. There should be a personal touch for all of the designs, making it clear that these items belonged either to a specific Relentless or a specific group of Relentless.

Relentless weapons tend to be like frost brand weapons, though they deal an additional 1d6 psychic damage on a successful hit and convey resistance against psychic damage when held. If you roll a natural 20 on your attack roll, the target of the attack must make a Charisma saving throw (DC 15) or gain one level of exhaustion. You may remove one level of exhaustion you possess when this occurs.

On the armor front, the Relentless armor expects you will never take it off if you can help it. After you complete a long rest in which you have stayed in your armor, you have advantage against becoming charmed or frightened, and have advantage on saving throws against exhaustion. If you were exhausted when you completed the long rest, you decrease your current exhaustion level by two, instead of one.

If you are attuned to both a Relentless weapon and suit of armor, you may no longer gain Inspiration. However, whenever you would gain Inspiration, it is as if you have completed a Short Rest – including you being able to spend hit die for healing as a reaction to this occurring.

In Summary

The Relentless should be an awful threat for adventurers in the Astral plane, and it should integrate rather nicely with exhaustion, while also laying some groundwork to mess with Inspiration. Their opposite number will certainly deal with Inspiration, while interacting with exhaustion in a similar way. In theme, they are a combination of vampires and slasher villains. They should be an implacable force that is terrifying, but not overly punitive for players to interact with. It should feel threatening and time-sensitive, but not a foregone conclusion of loss.

There are specific gaps here by design. Rather than design every item or every Relentless, this should be a framework to work from with minimal effort.


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