The method used for rolling up uncommon flaws is different than for other mutations. Instead of selecting a category (minor, medium, or major) then rolling on the appropriate column, a player who takes an uncommon mutant flaw rolls on the full list instead. If the result is not allowed (such as a near-human rolling a major flaw), simply reroll until an appropriate flaw is gained.
| d% | Category (BPs) | Mutant Flaws | Description | Advancement |
|---|---|---|---|---|
| 1-6 | Minor (2 BPs) | Anosmia | No sense of smell (or taste), -2 on all Fort saves vs. injested and inhaled poisons. | None. |
| 7-12 | Minor (2 BPs) | Decreased Charisma | -2 to Charisma. | Increase penalty by -1. |
| 13-18 | Minor (2 BPs) | Decreased Intelligence | -2 to Intelligence. | Increase penalty by -1. |
| 19-24 | Minor (2 BPs) | Decreased Wisdom | -2 to Wisdom. | Increase penalty by -1. |
| 25-29 | Min/Med (3 BPs) | Frenzy | Enters frenzied rage when damage is suffered in combat. Can only use natural weapons, must continue attacking until rage has ended. | Enters frenzied rage when non-combat damage is suffered. |
| 30-35 | Min/Med (3 BPs) | Insensitive | Cannot feel pain; GM tracks hp secretly. | None. |
| 36-39 | Min/Med (3 BPs) | Cystic Fibrosis | Lifespan of 20+2d10 years, -2 on Con checks. | Reduce lifespan by 10 years, additional -2 on Con checks. |
| 40-43 | Min/Med (3 BPs) | Sickle Cell Anemia | -1 to Strength, -2 on all Fort saves. | Increase penalties by -1 and -2, respectively. |
| 44-48 | Medium (4 BPs) | Decreased Constitution | -2 to Constitution. | Increase penalty by -1. |
| 49-53 | Medium (4 BPs) | Decreased Dexterity | -2 to Dexterity. | Increase penalty by -1. |
| 54-58 | Medium (4 BPs) | Decreased Strength | -2 to Strength. | Increase penalty by -1. |
| 59-62 | Medium (4 BPs) | Discordant Pheremones | -6 penalty on Cha-related interaction skills with living creatures. | Increase penalty by -2. |
| 63-66 | Medium (4 BPs) | Festering Sores | Decrease max Dex bonus of armour by -2 and increase armour penalty by +4. | None. |
| 67-70 | Medium (4 BPs) | Learning Disability | Character receives 2 less skill points/level than normal (×2 for starting characters, min). | Increase penalty to 4 less/lvl, 6 less/lvl. |
| 71-76 | Medium (4 BPs) | Low Creep Threshold | Long-term Creep threshold reduced by half. | Reduce by half again. |
| 77-80 | Medium (4 BPs) | Morbidly Obese | -1 to Dexterity and Charisma, speed reduced by 5 feet. | Increase penalties by -1, decrease speed by 5 feet. |
| 81-83 | Medium (4 BPs) | Neurofibromatosis | -1 to Dexterity and Charisma; -2 on vision-related Awareness checks. | Increase penalties by -1 and -2, respectively. |
| 84-86 | Medium (4 BPs) | Pituitary Deformation | Lifespan reduced by half, suffers age penalties early. | Lifespan reduced by half again. |
| 87-89 | Medium (4 BPs) | Seizures | 10% chance of suffering seizures at the start of combat. | Increase chance by 10%. |
| 90-92 | Medium (4 BPs) | Unreactive | -6 to initiative. | Increase penalty by -2. |
| 93-94 | Med/Maj (5 BPs) | Blood Hunger | Must consume blood or take 1d4 Con damage per day. | Double consumption requirements, increase damage die (1d6, 1d8). |
| 95-96 | Med/Maj (5 BPs) | Poor Dual Brain | 10% chance of suffering Confusion (as spell) at start of combat. | Increase chance by 10%. |
| 97-98 | Major (6 BPs) | Ultraviolet Ignition | Daylight burns for 1d6 damage/round. | Increase damage die (1d8, 1d10). |
| 99-100 | Major (6 BPs) | Weapon Incompetent | Never proficient with weapons (other than natural ones). | None. |