The Elder Scrolls' Dark Brotherhood is one of the darkest, most fascinating questlines players can embark on in the role of an assassin. Skyrim, particularly, brought this group back with all new original members with their own backstories and personalities.
The Dark Brotherhood is perhaps one of the most detailed and complex stories in Skyrim, with bizarre characters capable of bringing the dire group to life. They bring a sense of unhinged sanity to the otherwise bright environment and interact in a unique storyline like none other in the world.
Lis the Spider
Lis is a tamed Frostbite spider but still part of the Brotherhood, no doubt. She can be seen in her little spider nest corner of the Sanctum and is known to be Gabriella's pet. Though she is not hostile to the Dragonborn or other members of the Dark Brotherhood, she does attack later on during the Imperial invasion.
Lis isn't a crucial member of the Brotherhood, as she doesn't help the Dragonborn in any way or assist in pushing the storyline along. She is an interesting small detail. However, that explains more about Gabriella's nature. On closer observation of Lis, players can find bones around her nest, suggesting the Brotherhood must have fed their victims to her. The Dragonborn can get themselves a pet much like this as part of, Pets of Skyrim, one of the best Anniversary Edition quests.
Veezara
Veezara is an Argonian and Shadowscale at his birth, as he explains to the Dragonborn. He plays a minor role in the questline but still has his own unique backstory that the player can learn about by speaking to him.
Veezara, during his conversation with the Dragonborn, explains he is a Shadowscale, meaning he is an Argonian born under The Shadow sign and trained at birth in steal and combat. He was once employed by the King of Black Marsh as one of his personal assassins but believes he is the last living member of that order. Veezara assists the Dragonborn in an escape during one quest in the story, but unfortunately, he is later killed by the Pentius Oculatus.
Arnbjorn
Arnbjorn is the husband of Astrid and the werewolf of the group. He is a simple, to-the-point kind of character that will refer to the Dragonborn, no matter their relationship, by nicknames, such as 'lambshank,' 'beef roast,' or 'tidbit.'
Although Arnbjorn is not too interested in speaking to the Dragonborn, he does speak about his backstory as an ex-member of the Companions—where he received his lycanthropy. He was kicked out of the guild for his unorthodox methods but undoubtedly would have been one of the best members of the Companions due to his skill with two-handed weapons and stealth abilities. However, he doesn't play a major role in the story and is another member to be killed in the invasion of Sanctuary.
Gabriella
Gabriella is the Dunmer, or Dark Elf, member of the group. She, along with Festus, are the only ones seen in these shrouded robes instead of the Brotherhood armor and usually can be seen in the alchemy area or the dining hall.
Gabriella is one of the few members of the Brotherhood, besides Cicero, that appreciates the safe arrival of the Night Mother in the sanctuary and expresses her belief that the Mother should be 'respected.' She is one of the most sarcastic members as well and usually has a snarky reply if the Dragonborn attempts to ask her questions. She isn't one of the characters who survive the invasion, but she does help devise a plan with Astrid to weaken the Pentius Oculatus and asks the player to kill Gaius Maro to receive a special reward on the side.
Festus Krex
Festus Krex is the elder member of the Brotherhood, who describes himself as "the cranky old uncle who nobody talks to." Although he seems standoffish and cold to the Dragonborn at first, he later admits he was wrong about them.
Festus is the only member of the Brotherhood who uses magic as his only weapon. When asked about himself, he explains how he was a child prodigy who taught himself all his spells and mastered them by thirteen. He was a member of the Collge of Winterhold but left due to the lack of appreciation for Destruction spells. The player can complete a side quest for Festus entitled "Recipe for Disaster" to receive the Nightweaver's Band, but sadly Festus is killed during the invasion and plays no further part in the group.
Babette
Although Babette appears to be a young child, she is a fierce member of the Brotherhood and a vampire. Since being bit by a vampire as a child, she has remained in her young form, but she is actually over three hundred years old, suggesting she was alive during the Oblivion Crisis. It would also make her older than Festus.
Babette is not only one of the most intriguing characters of the Brotherhood—admitting she uses her innocent appearance to her advantage for killing—she is also one of the most useful. She has an affinity for making potions and can be seen working in the alchemy lab most of the time. Players can purchase potions or alchemy ingredients from her and train in the skill of alchemy. Babette is one of the few members to survive the invasion and continues to be an available vendor once the new Sanctuary is created.
Nazir
Nazir is a Redguard member of the Brotherhood, and although he isn't the leading figure of the group, he still amounts to that in the questline. He is one of the only members who isn't dressed in Brotherhood attire. Instead, he can be seen wearing Hammerfell clothing.
Nazir is the only other member, besides Babette, that survives the events with the Imperials' attack and continues to grow the Brotherhood back up in the new Sanctum in Dawnstar. Although several shared his distaste for Cicero, he is one member who distrusted the Jester from the very first moment he stepped in. Nazir is also responsible for giving the Dragonborn contracts and pays decent gold for completing each one. He also serves as a trainer in Light Armor up to master level.
Astrid
Astrid isn't available as a follower or spouse—since she's already married to Arnbjorn—but she is one of the best members of the Brotherhood because of the role she plays as leader of the group and part of some of the best quests in the base game.
Astrid is introduced to the character at the very start of the Dark Brotherhood, where they must go through an intense initiation to decide if they are worthy of joining. She proves to be a confident leader, constantly stating she is more competent without the strict rules of The Five Tenets. She later sees the Dragonborn as a threat and rats them out to the Pentius Oculatus but regrets this after other members are killed. She is a favorite character due to her unique animations and firm leadership, although she is killed later in the questline.
Cicero
Cicero is undoubtedly one of the best followers players can get in Skyrim and one of the most unique characters seen around the world. Though he is a deceiving and unpredictable character that leads to many problems with the Dark Brotherhood, he is perhaps one of the most intriguing members.
Cicero is first seen outside of Whiterun, where he asks for the Dragonborn's help in fixing his wagon as he's attempting to move the Night Mother to the Brotherhood Sanctum. His stunningly different voice acting, animations, and unhinged personality make him an interesting character to interact with. While some players might agree with the other members of the Brotherhood that he's annoying and has wrong intentions, others might appeal to his eccentric persona. If the player chooses to spare his life during the questline, he can become a follower—the only member capable of doing this.