The shards drop off of almost any mob in the zone, the most common being Shao-Tien mobs and tricksters. Their drop rate is VERY VERY low, Two other guildies and myself each have one as of right now but so far that is it. I tried testing this but it didn't do very well for a couple of reasons.
A- Warrior Singular CC sucks for prot (easiest farming for sustained HP, better with AOE)
B- The CC I like isn't updated it seems
C- Pathing issue causing character to just sit there
D- Fights too many spiders and not a very well populated zone for consistent spawns (imo)