The Subway Cluster

The Subway Cluster is the cluster consisting of Foil, March, and Homer.

Structure
Unlike other cluster groups, their interaction is mostly limited to a strong personality bleed-over, where unused skills and habits get shunted to other clustermates, but even in this case all clustermates mostly benefited from it (at least in a way shards capable of delivering it). Kiss/Kill dynamic arose later, in a more general manner.

Shards
Shards of the cluster collectively call themselves Three Faces and use plural first-person pronouns in narration. They are highly cooperative. They pool resources and readjust powers on the fly for hosts' benefit. However, clusters' shards are patronizing and distant to their hosts.

Background
In 2008, Lily was attacked by her sister, who was acting strange and violent. Their struggle knocked them and several people onto the tracks. The subway train came immediately after, causing several people to die and three people to trigger. All resulting parahumans continued with their lives for a time being.

Homer tried to contact and help his clustermates. Later he was killed due to wrong moves in New Yorks criminal circles.

March had near-death experience from dealing with smugglers cluster and became obsessed with unification of her cluster.

Post-Timeskip
March came after Flechette, now renamed Foil, two times while in Brockton Bay. On the second 'visitation' March kidnapped Foil's leman Parian.

Gold Morning
March and Foil survived the event.

Early-Ward
They met again at the Mathers Compound Assault, while March left amicable after a conversation with Parian, Foil thought it likely she might be hanging around ready to ambush them.

Post-Goddess' Takeover
March casually unleashed three broken triggers, and unwittingly produced new multidimensional S-class threat.

At the end of the same night Foil, faced with consequences of March's exploits and her fears, decided to eliminate March for good.