|“||You are no longer just you.||”|
Clusters are groups of sensates. Every sensate is part of a cluster, which can be as small as 2 or 3 or as big as 10 to 12. The cluster at the heart of Sense8 has 8 members and is considered an exceptionally and unusually large cluster. Members of a cluster are born on the same day at the same moment. As Jonas stated that "No matter how far across the world a cluster is scattered the first breath they take, they take as one".
A cluster has to be reborn by a sensate outside the cluster activating their innate connection to each other, called birthing. Before this connection is activated sensates are, for the most part, ordinary humans with the exception of occasionally forming a psychic link to other sensates via direct eye contact, like Will Gorski with Sara Patrell or Riley Blue with Yrsa when they were both children/unborn sensates. However, these connections are not as strong as the connections formed by "reborn" sensates and "unborn" sensates may form no connections. As seen when Lito Rodriguez formed no psychic connection to Raoul Pasquale when they met due to Lito being an "unborn" sensate. The parent of the cluster can be male like the father of Jonas's cluster or female like the mother of the 8/8 Cluster, Angelica Turing. Sensates who birth clusters can give birth multiple times to different clusters throughout their lives, as seen with the father of Jonas's cluster, an elderly thai man, who was surrounded by all 80 of his sensate "children" when he died or Angelica Turing who birthed 2 clusters before her death.
Parents are the only sensates that can mentally contact the entire cluster without being part of the cluster itself. This is limited, however, as Jonas has stated that sensates outside of a cluster can only visit and not share but it is implied that a clusters parent can communicate with their "children" with no language barriers. A clusters parent passes on a fraction of their memories, sense experience, and consciousness to the clusters they birth in the same way a physical birth passes on genes. Despite her death, a part of Angelica Turing's mind still lives within the 8/8 Cluster and sometimes appears to them. Sensates who are neither members of the same cluster nor the clusters parent can only visit sensates outside their cluster once they make direct eye contact with them.
Once established, the bond between the sensates within a cluster builds up over time, to the point where members of the cluster can share and visit each other easily and understand one another despite speaking in different languages. Jonas told Will when they first met: "You have seven other selves now", Exemplifying the bond within a cluster. Each Sensate within the cluster can be considered one part of a larger whole. While all sensates who make direct eye contact can visit each other, only sensates within the same cluster can share skills, languages, and knowledge. Sensates communicate with other sensates telepathically (mind to mind) but often speak out loud when visiting another sensate and appear to be talking to nothing by outside observers, as shown when Diego walked in on Will Gorski apparently kissing the air while Riley Blue was visiting him. However, sensates can learn to communicate and interact with each other purely in their minds, exchanging conversation and physical contact without speaking or touching.
The members of a cluster are often very different from one another in terms of race, gender, sexuality and country of birth. As Amanita Caplan's mother Grace told Nomi Marks, "The engine of evolution is variation. I'd imagine to become something more than what evolution would define as yourself, you'd need something different than yourself". The connection of a cluster over time becomes incredibly intuitive, even functioning on a subconscious level, to the point where a sensate who finds themselves in emotional turmoil will often instinctively visit and share with members of their cluster who can offer a perspective or life experience that can help them.
It is shown throughout that clusters are very important and precious. Angelica committed suicide to protect the cluster she had just birthed, and later the piece of her mind that still endured within the cluster re-appeared to Will in I Can't Leave Her along with Jonas pressuring Will to commit suicide to protect the location of the other six members of his cluster. Yrsa also appeared to Riley and told her that she needed to 'protect them', meaning the rest of the cluster.
- August 8 cluster. All eight sensates have been revealed and are the main characters of the show.
- Angelica and Jonas' cluster. Revealed to have six members.
- Whispers' cluster. Whispers killed the other 7 members, the Mother felt each one die, and Whispers experienced each of their deaths as both the murderer and the murdered which made him afraid of death.
- Yrsa's cluster. Yrsa mentions at least one of their members is dead.
- Lila Facchini's cluster. At least 8 members, including Maitake and Josh played by actor Josh Grothe. Rivals of August 8 Cluster.
- Angelica's firstborn cluster. First cluster Angelica gave "birth" to. 7 members total, including Raoul Pasquale, Habib and Todd W. McCarver.
- Old Man of Hoy's cluster. At least one man dead.
- Puck's cluster. No information on other members. Sutra may or may not have been a member.
- "Allegretti" twins cluster. Part of the Archipelago network. One of the partners at Lawrence Marks' law firm is also named Allegretti, but little else is known about the cluster.
- Niles Bolger's cluster. It is implied that Niles is part of a cluster in security footage in S1E8.