The Cold Blade can be found in the campaign Under the Burning Suns, in the 4th scenario Descending into Darkness. (Located at x=12;y=16).
The unit who wields this blade will deal cold damage with its melee attack.
How odd. Someone has carved a crude fountain out of the stone at the end of the passage. The freezing water pours out into a large pool. At the bottom of the pool I can see a skeleton still gripping a sword. The blade seems to glow faintly blue. The pool isn’t very deep, I could easily wade in and pick it up. But someone else has carved a crude message in the wall. “If you dare to take this blade here, your greatest fear will surely appear.” It looks like a nice sword, but do I dare chance it?
The blade is chill to the touch and gives off a cold glow. I wonder how it came to be here.