Blood makes a good weapon. In fact, blood makes one of the best weapons I've seen in adventure mode. Here are its advantages:
- Blood is infinite.
- Blood is the fastest way to level throwing.
- Blood can crush skulls.
- Blood is free, and can be found anywhere.
- You always start out with it.
- You can drink it. Try drinking your sword when you're thirsty, I can guarantee you'll have a lot of Fun with that one.
Allow me to explain. (Note that most of this research was done by my brother, I just watched and experimented with it a bit on my own. He's the one who loves Adventure mode, I usually go in for Fortress mode.)
Blood is infinite, and the fastest way to level throwing, by which I mean you can stand in one place, scoop some blood off the ground, fling it at yourself (literally), scoop up some more and fling it again. This levels up your throwing skill remarkably quickly if you loop the same key combinations repeatedly, and the pool of blood will never run out.
Blood can kill, by which I mean, if you have high enough throwing ability, you can literally cup some of your own gushing blood in your hands, send it like a missile at the head of the bowman who gave you that wound, and crush his skull with it, all in one swift motion. You can knock out teeth and even sever the horns of a boogeyman without too much trouble. If you throw it at somebody's stomach, they're likely to start retching, and you can use their vomit against them in the same way (although that's a bit lacking in style). With high enough throwing ability, you can shatter just about any bone with ease, and a bit of the red liquid. If you're into using alternative weapons, you can use the blood as a melee weapon and beat your enemies into submission.
It's ironic that you can use the very life force of your enemies against them in such a devastating way. (Unfortunately, it's not quite as effective on stronger monsters such as bronze colossi.)