Blade Blood Plague.

Ones blood starts to crystalize and slices out of parts of the body, causing sharp formations where it leaks out. While this might seem to be something that would cause one to bleed to death, the crystalizing process keeps it from spilling all over and instead covers the body in sharp growths.

The most determined and vicious of the afflicted can use this to their advantage, throwing themselves into battle with even more of their body as a weapon. Even if their enemies survive, shards that break off into another's body can dissolve once it interacts with their blood, having the high potential of infecting the targets with this plague, and whatever other bloodborne diseases they carry as well.

If the victim does not shatter away the formations, eventually they will not be able to move without impaling themselves. In rare extreme cases this results in the plagued individual giving up and remaining in place, becoming a jagged spire of gleaming crystals, their bones buried beneath. Some think this was a mutation of the Gembond disease, others claim it is a malevolent curse.