You were born during the height of a great magical plague, to a mother suffering from an eldritch disease, or you suffered an eldritch pox as a child, such that your very soul now carries a blight of pestilence within it.
Class Skill: Heal.
Bloodline Arcana: Vermin are susceptible to your mind-affecting spells. They are treated as animals for the purposes of determining which mind-affecting spells affect them.
Bloodline Powers: You awaken and quicken the lurking pestilence in your own body or the surrounding world to wreak hideous malice, or to command and commune with agents of such plagues.
Plague’s Caress (Sp): At 1st level, you can make a melee touch attack as a standard action that causes a living creature’s flesh to break out into rancid-smelling pustules and sores for a number of rounds equal to 1/2 your sorcerer level (minimum 1 round). These sores cause the victim to become sickened for the duration of the effect; this is a disease effect. You can use this ability a number of times per day equal to 3 + your Charisma modifier.
Accustomed to Awfulness (Ex): At 3rd level, you become immune to the sickened condition and gain a +4 bonus on all saving throws against effects that cause nausea or disease. At 9th level, you become immune to the nauseated condition and to the debilitating effects of disease (but you can still be a carrier of diseases).
Shroud of Vermin (Su): At 9th level, swarms no longer see you as prey. You can walk among swarms without fear of being harmed by them at all, and by taking a standard action to mentally command a swarm in which you stand, you can direct that swarm’s attacks and movements as long as you have more Hit Dice than the swarm. Even when you aren’t standing amid a swarm, your body crawls with vermin, and their chitinous bodies increase your natural armor bonus by +1. At 11th level, this bonus increases to +2, and at 17th level it increases to +3.
Pestilential Breath (Su): At 15th level, the sickness within your body finally becomes so potent that your very breath is deadly. Once per day as a standard action, you can exhale a cloud of pestilence in a 30-foot cone. Those caught in the area of this miasmic cloud receive a single Fortitude save to avoid suffering the effects of two different diseases. The DC of this save is equal to 10 + 1/2 your sorcerer level + your Charisma modifier. You can choose what two diseases you inflict on each target that succumbs to your plague breath, but they must be two different diseases chosen from the following list: blinding sickness, bubonic plague, cackle fever, filth fever, leprosy, mindfire, red ache, shakes, or slimy doom. The victim suffers the initial effects of these two diseases immediately—use the diseases’ frequency and save DC normally to determine further effects as detailed on page 557 of the Pathfinder RPG Core Rulebook. At 17th level, you can use this ability twice per day. At 20th level you can use this ability three times per day.
Plague Carrier (Su): At 20th level, your touch inflicts mummy rot on those you strike. You can choose to suppress this ability for 1 round as a swift action. You can make a touch attack to inflict this disease on a target, or transfer it as part of an attack with any melee weapon or touch-based spell. The creature touched can resist contracting mummy rot by making a Fortitude save—the DC is equal to 10 + 1/2 your sorcerer level + your Charisma modifier.