You will find Arnbjorn in his werewolf form fighting Penitus Oculatus agents. You can try to help him, but his death is scripted and he will die even if you kill the agents around him. There is no way for you to save him.

“If you have a garden and a library, you have everything you need.” Cicero.

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.

Cicero will disappear after Destroy the Dark Brotherhood! even if he’s still waiting near Whiterun for Delayed Burial, if your on a PC you could try using commands otherwise i don’t think you can find him. Although Cicero will still be alive, unfortunately you can’t find him when you destroy the dark brotherhood.

Cicero is one of the best companions you can get in Skyrim for a plethora of reasons. He’s an assassin with incredibly high stats, and he’s got one of the most well-developed personalities in the entire game.

Cicero’s reward is slightly higher than Vantus’ reward, should the Dragonborn choose to help Vantus and report Cicero. If the Dragonborn chooses to report Cicero to the guards (as Vantus initially wishes to do) however, Cicero will be arrested and led away.

Probably mid-30s. His journals are dated to 15 years prior to the game, which makes sense, thinking he was between 18-22 when he joined.

Cicero is an assassin and the Keeper of the Dark Brotherhood. The coffin he is transporting contains the remains of the Night Mother.