From Compendium of Worldly Lore
Cancer Mages are vile casters and sneaky roguelikes that spread disease and pain around the battlefield, they have a cancerous companion with a plethora of abilities that help control vermin and small diseased beasts and at the highest level can even turn into a disease.
Role: Spell DPS
Characteristics: Caster that controls and spreads disease
Source: Book of Vile Darkness
Game Rule Information
The Cancer Mage has the following game statistics.
Abilities: Wisdom for your abilities, Dexterity for armor class and to hit with sneak attack, Constitution for more HP, Intelligence for your diseases and viruses.
Alignment: Any Evil
Hit Die: d6
Starting Gold: N/A
Class Skills
The Cancer Mage's class skills are Alchemy (Int), Balance (Dex), Bluff (Cha), Climb (Str), Craft (Int), Disable Device (Int), Disguise (Cha), Escape Artist (Dex), Gather Information (Cha), Heal (Wis), Hide (Dex), Intimidate (Cha), Intuit Direction (Wis), Jump (Str), Knowledge (nature) (Int), Listen (Wis), Move Silently (Dex), Pick Pocket (Dex), Profession (Wis), Ride (Dex), Search (Int), Sense Motive (Wis), Spot (Wis), Swim (Str), Tumble (Dex), and Use Rope (Dex).
Skill Points at 1st Level: (6 + Int modifier) × 4
Skill Points at Each Additional Level: 6 + Int modifier
Class Features
All of the following are class features of the Cancer Mage.
Weapon and Armor Proficiency: A Cancer Mage is proficient with whatever they were already proficient with.
Sneak Attack: If a cancer mage can catch an opponent when she is unable to defend herself effectively from his attack, he can strike a vital spot for extra damage. Basically, the cancer mage's attack deals extra damage any time his target would be denied a Dexterity bonus to AC (whether she actually has a Dexterity bonus or not), the cancer mage's attack deals +1d6 points of damage. This extra damage increases by +1d6 points evert four levels (+2d6 at 5th level and +3d6 at 9th level) Should the cancer mage score a critical hit with a sneak attack, this extra damage is not multiplied.
It takes precision and penetration to hit a vital spot, so ranged attacks can only count as sneak attacks if the target is 30 feet away or less.
With a sap or an unarmed strike, a cancer mage can make a sneak attack that deals subdual damage instead of normal damage. He cannot use a weapon that deals normal damage to deal subdual damage in a sneak attack, not even with the usual -4 penalty, because she must make optimal use of her weapon in order to execute a sneak attack.
A cancer mage can sneak attack only living creatures with discernible anatomies—undead, constructs, oozes, plants, and incorporeal creatures lack vital areas to attack. Additionally, any creature immune to critical hits is similarly immune to sneak attacks. Also the cancer mage must be able to see the target well enough to pick out a vital spot. A cancer mage cannot sneak attack while striking at a creature with concealment or by striking the limbs of a creature whose vitals are beyond reach.
If a cancer mage gets a sneak attack bonus from another source (such as rogue levels), the bonuses to damage stack.
Disease Host Ex: At 1st level, a cancer mage suffers no ill effects of diseases, except for purely cosmetic ones such as boils, pockmarks, watery eyes, blackened skin, hair loss, foul smell, and so on. The cancer mage becomes a carrier of every disease he encounters, though he remains immune to most of their effects. However, the cancer mage takes 1d6 points of damage per caster level if someone casts a cure disease spell or effect on him (he can make a Fortitude save to try to resist the effect). Furthermore, if the cancer mage has a cancerous companion (see below), he loses all abilities gained from the companion for 1d10 days after being the subject of a cure disease spell.
Contagion Sp: Beginning at 2nd level, the touch of a cancer mage carries a contagion spell once per day per class level. The DC for the target's saving throw is 13 + the cancer mage's Wisdom modifier.
Cancerous Companion Ex: At 2nd level, a cancer grows within the cancer mage, forming a large tumor. This cancerous growth gains intelligence and a personality distinct from the cancer mage. The companion and the cancer mage can communicate telepathically. When needed, the cancerous companion uses the cancer mage's scores for saves, ability scores other than Intelligence, and so forth. The cancerous companion gains abilities as the cancer mage gains levels.
Tatterdemalion Ex: Gathering scraps of clothing and old, discarded rags, a 3rd-level cancer mage is able to make such articles into light armor with a the following stats: armor bonus +4, maximum Dex bonus +5, armor check penalty —1, arcane spell failure 15%, speed 30 ft./20 ft., weight 20 lb. Only a 3rd-level or higher cancer mage can wear this armor and gain these benefits; other wearers treat it as padded armor. This armor is considered masterwork quality and can be fashioned into magic armor.
Poison Sp: Once per day per class level beginning at 3rd level, the touch of a cancer mage carries a poison spell. The DC for the target's saving throw is 14 + the cancer mage's caster level.
Children of the Night Su: A 4th-level cancer mage commands the lesser creatures of the world and can call forth a swarm of 2d6 Small monstrous spiders or a pack of 4d8 dire rats or a swarm of 10d10 bats, once per day, as a standard action. These creatures arrive in 2d6 rounds and serve the cancer mage (understanding his mental commands) for up to 10 minutes per class level.
Viral Agent Su: At 5th level, a cancer mage befriends a disease or virus that infests his body. He supernaturally enhances a disease, making it smarter by giving it a point of his own Intelligence. He establishes a telepathic link with the disease that functions at a range of one mile per class level of the cancer mage.
The cancer mage can then attempt to infect a target with his viral agent, using his contagion ability. If successful, the viral agent can tell the cancer mage telepathically what its host experiences. In all other respects, the viral agent is a normal disease; if the victim fights it off or a cure disease spell is used, the disease and the viral agent die. The cancer mage regains his Intelligence point 24 hours after the viral agent dies. The cancer mage can create as many viral agents as he is willing to devote Intelligence points toward.
Infect Wound Ex: Once per day per class level beginning at 6th level, a cancer mage can infect his foe with an infectious taint after making a successful melee attack. The foe takes 1 point of Constitution damage and must make a Fortitude save (DC 10 + cancer mage's class level + cancer mage's Wis modifier) 1 hour later or take a further 1d6 points of Constitution damage.
Insect Plague Sp: At 7th level, a cancer mage invokes insect plague once per day as a cleric of his class level.
Insect Armor Su: By allowing insects and worms to crawl over his body, a 7th-level cancer mage gains a +4 natural armor bonus. The cancer mage cannot wear armor heavier than light armor and keep this benefit, however.
Viral Ally Su: In a fashion similar to the viral agent ability, a cancer mage of 8th level or higher can create a viral ally by devoting 3 points of Intelligence to a disease or virus in his system. The cancer mage can then bestow his viral ally upon a humanoid victim using his contagion ability, and the viral ally can communicate telepathically with the cancer mage. The viral ally (and thus the cancer mage) controls its host as surely as with a dominate person spell, although the host gets no separate saving throw to avoid the dominate person effect. The viral ally is a normal disease, however, and the victim can fight it off with successful Fortitude saves or a cure disease spell, either of which kills the viral ally. The cancer mage regains his missing Intelligence points 24 hours later. A cancer mage can create as many viral allies as he is willing to devote Intelligence points toward.
Disease Form Su: At 10th level, a cancer mage gains the ability to transform into a disease once per day. (This ability also affects up to 100 pounds of gear the cancer mage is carrying, plus tatterdemalion armor, insect armor, and a cancerous companion.) As a disease, the cancer mage is intangible and invisible to standard methods of observation, even blindsight. Creatures with the scent ability note a foulness in the air. The cancer mage cannot move, except with the wind (if any), or within a host.
The cancer mage may adopt his disease form as a standard action, attempting to infect a living creature within 100 feet. A potential victim must succeed at a Fortitude save (DC 20) to avoid being infected with the cancer mage. Any creature that comes within 10 feet of a cancer mage in disease form is subject to the saving throw to resist infection as well. Once inside an infected host, the cancer mage deals 1d3 points of Constitution damage per day after a 24-hour incubation period. The victim has no way of knowing that the cancer mage is anything other than a normal illness.
The cancer mage travels with the victim, aware of whatever the victim is aware of. A number of times per day equal to the cancer mage's Charisma bonus, the cancer mage can attempt to force the victim to take one round's worth of actions of the cancer mage's choosing; a successful Will save (DC 18 + cancer mage's Wis modifier) allows the victim to resist this. While controlling his victim, the cancer mage has access to all skills, feats, spells, and special abilities of the host, plus any of his own that he can use in his disembodied state. The cancer mage can leave his host at any time, allowing the victim to recover normally. The victim can also attempt to force the cancer mage out by making Fortitude saves as if the cancer mage were a normal disease. Heal checks help the victim as they would normally. A cure disease spell kills the cancer mage if he fails a Fortitude save (calculating the save DC as for spells of the same level). Even if the cancer mage succeeds at the saving throw, he is forced to reassume his material form adjacent to the victim.
A cancer mage can remain in disease form as long as he desires, or he can return to his natural form and be done with the disease form for that day. While in disease form, the cancer mage does not need to eat, sleep, or drink, and he does not age. A cancer mage could remain dormant in a room for a hundred years, then take his material form or infect a new victim.