Mirefleck was a female horde rat who was promoted to the rank of captain soon before Ungatt Trunn's assult on Salamandastron. She was the leader of the group that discovered Stonepaw's position. After the other hares trapped in the cave escaped, she was demoted.
As her punishment, she was forced (with Groddil and Fraul) to search the mountain cavern for the hares' means of escape. Realizing that Ripfang and Doomeye would whip her for the slightest disobedience, she was always painfully obedient and polite, practically fawning at their feet until she got on their nerves. Because of that, they tested to see if she was faster than an arrow. Mirefleck was slower than an arrow, and thus perished. She was apparently a skilled warrior, and was one of the Blue Horde's most respected Captains for that.