I assume this blood is supposed to be Fader's, right? Because... the rocks Fader died on were at the base of the Causeway pillars, right at sea level, and I don't see why the blood wouldn't have been rapidly washed away in the same torrential waves of the storm you mention would (and did) wash away the body. I thought it was kind of obvious when I had Murder licking up some random blood near the school that it would be Fader's. When no-one objected, I thought that meant it was okay for the blood to still be there. Of course, it's not like the corpse magically vanished, leaving only a pool of blood - most of it would be gone as well, but some traces should still be visible. Silver likely wouldn't have found it on his own, but Murder (who you will see more of later) likes to check everything out and would definitely find it, even if there was only a little left.