Conditions: Blood Magic Ailments
Sometimes, poisons and diseases are just not enough to represent the kind of wretched afflictions that forbidden magic is capable of producing. Legends speak of heroes struck by terrible blood hexes and of reckless warlocks who fouled their own blood in their pursuit of power.
Blood magic aliments are magical afflictions that are not curses, diseases, or poisons, but linger in the blood of a creature until they are cured. Creatures that don't have blood can't suffer from blood magic ailments.
These ailments represent a form of magic that is both more primal and also more twisted than normal curses as they can't be removed with most effects that remove curses. They are inherently more magical than disease, and can't be removed by any disease-curing spells. (They are fundamentally plot components more than they are gameplay elements, and they should be treated as such within your campaign.)
When to use Ailments
As a DM, you choose when to make use of ailments and when not to. You can use ailments as a response to the actions of your player characters or as independent plot elements on their own.
You might impose a random blood magic ailment on a player character that you feel is abusing or misusing the gameplay mechanics of blood magic. If a player is trying to create an infinite loop of spell slots or hit points, or is otherwise attempting to break the game using aspects of the rules that were unforeseen, you can use the threat of blood ailments as an in-narrative way to balance out those actions and add risk to their reward.
You can also use blood magic ailments to underscore the power or danger of blood magic. For example, if a villain targets a player character repeatedly with blood magic, you might use a blood magic ailment to show how powerful the villain and its forbidden magic can be. You could also use blood magic ailments to represent the eerie eldritch mutations caused by stray wild magic or uncontrolled demonic portals.
You can even use these ailments to apply permanent character traits to a creature. For example, many of the ailments can represent incurable genetic diseases or mutations. Others can be used to represent long-term mental illnesses or personality changes.
Blood magic ailments can also be repurposed as part of other mechanics or effects. You might use one blood magic ailment as one of the symptoms for a disease of your own creation, as the effect for a homebrew poison, or as the primary component of a curse.
These concepts apply to NPCs as well as PCs. Blood magic ailments work well when applied to NPCs, since they can impact the plot of a campaign without making the play-experience worse for any player who doesn't enjoy these kinds of game mechanics. An ailment that befalls a beloved NPC can sometimes become the best motivation for an adventure.
Acquiring Ailments
When a creature is subjected to a blood magic ailment, it might be able to make a saving throw to resist. These are generally Charisma or Constitution saving throws. If the ailment is acquired through physical means, then it uses Constitution, and if it is acquired through magical or spiritual means, it uses Charisma. You can determine the DC for these saving throws by adding 10 + half the creature's CR or leveL or by using your own means. If the ailment is acquired from spellcasting, you can use the spellcaster's spell save DC, even if it is the creature's own spellcasting that caused the ailment.
However, there is often no saving throw to resist the acquisition of a blood magic ailment. As a DM, you can always choose whether a creature can resist the ailment with a successful saving throw or not. Ailments that can not be resisted are sometimes more appropriate.
Curing Ailments
Blood magic ailments are not diseases and so cannot be cured by effects that remove a disease, nor are they poisons. Similarly, they're not curses, so effects such as the remove curse spell will not remove them.
Instead, blood magic ailments can only be removed by plot-relevant actions dictated by the DM. For example, an ailment might only be able to be cured through a special ritual that can only be performed at a specific location, or using specific rare materials. You might decide that an ailment can only be cured using a remedy made from ingredients obtained through difficult adventure, or that an ailment can only be removed by a specialized healer, such as a rare celestial or benevolent fey.
In the end, remember that these ailments are meant to improve your game and the experience for all your players, not detract from it. Try to use these ailments as opportunities for further adventure and excitement. If your players do not enjoy the experience, try to provide easier ways to remove the ailments, and perhaps even avoid their use in the future.
Ailments
Dead Blood. It cannot regain hit points by spending hit dice or finishing a long rest, and it fails all saving throws against poisons and diseases.
Blood Madness. Each time it finishes a long rest, it rolls on the Long-Term Madness table and the Indefinite Madness table, and it experiences both results until it finishes another long rest.
Pale Blood. Its blood loses some energy-restoring capacity. To reduce its exhaustion by one level, it must finish a number of long rests equal to 8 - its Constitution modifier (minimum of two long rests), instead o f only one. In addition, its blood cannot be used for blood magic.
Diluted Blood. Its emotions are influenced against its will. It is reserved, aimless, and emotionless, unable to summon almost any amount of urgency or motivation to act.
Hot-Blooded. Its emotions are influenced against its will. It is passionate, excitable, and easy to anger, unable to calm down or act slowly.
Blood Zeal. Its blood is overly aggressive to toxins. When it becomes poisoned or diseased, it takes necrotic damage equal to its level or challenge rating (minimum 1 damage). While it remains poisoned or diseased, it cannot regain hit points by spending hit dice or finishing a long rest, and it takes necrotic damage equal to its level or challenge rating (minimum 1 damage) every hour.
Rotten Blood. Its blood decays quickly, and smells very strongly of rot and death as soon as it is spilled. It has vulnerability to necrotic damage, and while it is missing hit points it gives off a disgusting smell that enables those who can smell to track it without requiring an ability check.
Inert Blood. It regains half as many hit points from spells and magical effects that restore hit points. In addition, its blood cannot be used for blood magic.
Blood Torpor. Its blood is slow to move after sleep or repose. To finish a long rest, it must roll 1d4 - 1 and rest for that many additional hours. In addition, its blood cannot be used for blood magic.
Fearful Blood. Each time it finishes a long rest, it rolls twice on the following table.
| Die Roll | Dmg Type | Creature Type |
|---|---|---|
| 1 | Acid | Aberration |
| 2 | Cold | Celestial |
| 3 | Fire | Construct |
| 4 | Force | Dragon |
| 5 | Lightning | Elemental |
| 6 | Necrotic | Fey |
| 7 | Poison | Fiend |
| 8 | Psychic | Giant |
| 9 | Radiant | Ooze |
| 10 | Thunder | Undead |
Until it finishes another long rest, it has a terrible phobia of the damage type from its first roll on the table and the creature type from its second roll. Whenever it encounters a creature of that type or sees a creature deal damage of that type, it must succeed on a DC 15 Wisdom saving throw or become frightened. It stays frightened until it can't see or hear the creature for an entire minute.
Blood Imbalance. Its blood flow becomes easier to disturb and its blood cannot be used for blood magic. Also, when it moves more than 30 feet on its turn, or when it moves more than 10 feet on any other turn, it must succeed on a DC 15 Constitution saving throw or be light-headed until the end of its next turn. Being pushed or pulled counts for this effect, as does falling. While light-headed, it can't concentrate or take actions, and its speed is halved.
Fouled Bloodline. Any children it propagates in this state will be sickly, malformed, and infertile for their entire lives. In addition, its blood cannot be used for blood magic.
Eldritch Veins. Its blood glows through its veins and shines from under clothing, radiating a noticeable aura of eeriness. It has disadvantage on ability checks made to hide, ability checks made to disguise it have disadvantage, and it can't benefit from invisibility.
Frigid Blood. Its emotions are influenced against its win. It is distant, depressed, and melancholic, unable to feel almost any joy or positive emotions.
Poisoned Blood. Its blood is poisonous to those who touch its wounds. While it has less than half of its hit points remaining, it deals poison damage equal to 5 + twice its level to any creature that willingly touches it.
Cursed Blood Whenever the target's blood is used for blood magic, it takes necrotic damage equal to twice its maximum number of hit dice. In addition, whenever it rolls initiative, it must also roll a d6. On a roll of 5 or 6, it suffers the effects of the bane spell for the next 10 minutes.
Blood Thirst. Its body becomes dependent on extra blood. It must drink blood instead of water to survive, though the blood need not be fresh and can come from any source other than itself.
Dry Blood. Its emotions are influenced against its will. It is cynical, fatalistic, and selfish, unable to regard others with empathy or expect good things from the future.
Possessed Blood. Any event that causes it great stress -- including entering combat, taking damage, experiencing fear, or having a nightmare -- forces the creature to roll a d6. On a roll of 5 or 6, it becomes incapacitated for 1 minute and falls prone, shaking and spasming for the duration.
Dire Hemophilia. It can't regain hit points by spending hit dice or finishing a long rest, and while it is missing hit points, it loses 1 hit point from internal blood loss every 1d6 hours.