Shadowmere is a mysterious undead black horse associated with the Dark Brotherhood. The horse's gender is undetermined; it is inconsistently referred to as both male and female. It has glowing red eyes.
The horse is seemingly immortal, having lived for over two hundred years. It is very hard to kill the horse in combat, due to its incredible regeneration. If slain, Shadowmere will reappear within days. The horse is of a magical nature, and is known to rise from the ground when summoned. It is always decorated with a stylized Dark Brotherhood saddle.
Shadowmere was once owned by Lucien Lachance, a Speaker for the Black Hand. The horse served him well, and Lucien was fond of it. In 3E 433, following the third Purification in the history of the Dark Brotherhood, Lachance gave the horse to his new Silencer as a token of his trust and love. By 4E 201, Shadowmere had come into the possession of Astrid, the leader of the last remaining Dark Brotherhood sanctuary. She eventually gave the horse to a new member of the Brotherhood who had been appointed as Listener by the Night Mother. Lachance, who served the Listener as a spectral assassin, continued to maintain a bond with the horse even in death.
- Doom Wolves are often used as mounts by the Dark Brotherhood, and are similar in appearance to Shadowmere.
- Dire Ponies are similar in appearance to Shadowmere, but smaller in stature and with a golden mane. The eyes of a Dire Pony only occasionally glow red. They are associated with dark cultists.