A hunter.

Out of the darkness came a hunter, and Jessica held her breath. He wore the standard garb of the Church-sanctioned hunters, and from his neck hung the hunter's mark. In one hand, he bore the serrated weapon that so many hunters wielded against the plagued beasts, and the standard hunter's pistol rested at his hip. He approached her cautiously.
"Be not afraid, lass." His accent was foreign to Yharnam, and sounded cultured to her ears. "I am not touched by the bloodlust, or any other lust for that matter." Jessica became aware of her partially torn dress and tattered cloak, and shrank in on herself. "How did you come to be in this place?"
"A... a Snatcher."
"I suspected as much. I believe they work for the School, to gather test subjects. And... they have their own appetites..." he mused, and Jessica shuddered at the memory of her violation. "Well, if you come with me, I can escort you to Oedon Chapel. You will be safe there until the hunt is complete this night. The incense there wards off the beasts." He extended a gloved hand, and she took it, letting the hunter help her up.
"Thank you. I'm Jessica, what's your name."
"My name is not important, lass. I'm just a hunter."
"Thank you, Master Hu-" she cut off suddenly as a flare of heat and pain swelled in her abdomen. She began coughing, and was alarmed when her sleeve came away from her mouth covered in blood and sputum.
"Let me see your eyes, lass." The Hunter tilted her head back to look into her eyes. "Did the Snatcher... take you?"
"Yes." Jessica nodded shamefully.
"Curses. You've been infected. You will die, or worse, unless..."
Jessica wailed. "Unless what?"
"You need a blood minister. The old blood will keep you alive. I can bring you to Iosefka's Clinic." He looked grim. "You will be bound by contract to the hunt for this night, but the blood will give you the strength to survive."
"And... if I don't?"
"I do not know if you can survive without it, or worse, you may be overcome by the curse yourself, and become a beast." The Hunter was dispassionate: he was simply laying out the alternatives. "The Black Church Hunters will not hesitate to dispatch you if they even suspect. Gascoigne and Henryk are in the hunt this night, and they are as efficient and ruthless as they come. I don't think you will be able to stay at Oedon Chapel unless you receive the ministration."