The system is done so all liquid types can cover stuff, at least one of the enemies that I remember will have acid instead of blood. The only exception I'll probably make will be water that will clean other liquids and apply wet status.
Viewing post in v0.3 preview
I'm not sure if I totally got across what I meant :) This is the best animation from Dwarf Fortress I could find briefly to illustrate it:
https://preview.redd.it/ai5hgyod89211.gif?format=mp4&s=a67a2970be0a1941c4c6e53b2db9496bf321f836
Blood flung off from those "k" creatures (goblins I think? Or kobolds?) flows down in the direction of the river flow. Not suggesting anything as crazy as the fluid dynamic systems DF has, but would it be worthwhile to have something like assign a directional flow to river tiles maybe on a per-zone basis, and have bloody or otherwise covered entities appear to release said liquid downriver and eventually dissipate? Would love to see corpses and other bloodied objects dumped in a body of water to behave the same way. On the other hand I also figure you're probably more amenable to complex additions when they actually effect gameplay mechanics :P