How do you kill someone with a liquid?

[vfinnigan]

That blood could carry a deadly disease. There's a reason why medical professionals wear gloves, masks, and such. Sure, it protects the patients. But especially when the medics are around a lot of bodily fluids and such, it protects them just as much.

[Moehwa]

perhaps like the film terminator, the liquid can turned into sharp knife for killing~

[monotone_ink]

There was this Japanese biological warfare research unit called 'Unit 731' back in World War II, where they performed a lot of human experimentation on Chinese prisoners.

For one of them, they 'tested' for remedies to frostbite. They would bring out a prisoner in the middle of the snow and have them stick their arm out in the open until they suffered from frostbite. They would then pour boiling water over the arm and wait for it to frostbite again. They repeated this process until the skin and flesh fell off.

There's no shortage of cruelty that can be done to a person, let alone just liquids.

[Egypt_Urnash]

Magically, blood is a powerful connection. Blood is your signature, blood is you. We could go further down fantasy magic paths and posit that this character's blood has the ability to change other people into them, causing massive problems as a significant portion of their body becomes someone else who must be attacked by the immune system. And possibly with the converted portion's immune system attacking the unmodified parts as well.

If they are attacking with their blood by using some kind of telekenisis then you could do some nasty stuff. Spray it in someone's nose. You know how when you get a sinus infection it feels like your head's gonna explode? Multiply that by a bit. Get it down someone's throat, use a thick blob to jerk the esophagus around, push down into the intestines and tie those into a hideous painful knot. Or push up into them from the other end if this is an X-rated affair.

Get it into someone's veins and you can do even worse. Make a nice big clot right in the middle of a major artery, jam up one of the heart's valves, or how about a lot of pressure on a blood vessel in the brain? That's pretty fatal.

[IdiotWithPencil]

The second way is to have work like a poison. In my story since the character is a demon, so when it mixes into human blood streams it begins to infect them.

ooooh actually you don't even need poison blood to kill somebody with that method just inject them with the wrong blood type and boom, instant death by their own Immune system, that or they get severely weakened

Edit: looked up things about wrong blood transfusion, seems one of the early symptoms is "a sense of impending doom" could be useful for a story where the blood manipulator losing and the other winning just for a very wrong feeling starting to creep in before they collapse of fever and shakes =P

[CatoCoyote]

My first instinct was expansion. You get an in to some body cavity and pump blood into it until the pressure gets too much. It doesn't have to do anything too visible either. That tactic can block airways, cause internal bleeding, send bone fragments where it has no good business being. If there's a wound and your character's got absolutely steller control they could selectively pop or choke organs. I'm sure that one concept could do a whole lot more than I thought of here, just pick an idea and run.