Lansor (played by Vaughn Armstrong) was a member of Seven's unimatrix and a former Borg drone designated as Two of Nine, Primary Adjunct of Unimatrix Zero One.
After temporarily being separated from Borg collective by the crash of their ship, Lansor, along with three other drones - Marika Willkarah, P'Chan and Seven - were joined in an ad-hoc collective linked directly through their subspace transceivers. When the drones were returned to the Collective, this anomaly persisted and after Seven's separation the three found themselves isolated in the hive mind. Lansor and the others managed to escape the collective and have their implants removed. However it was not possible for them to remove the transceivers, a condition that meant their ad-hoc collective persisted and never truly allowed for any of them to be alone. In 2376 the three former drones sought Seven's help in breaking the link so they could live as individuals.
Ultimately it was discovered that the only way they could exist separately was if transceivers were removed, the result of which would be death within a month. Lansor and the other two agreed to accept this shortened life as the cost for true freedom and left Voyager to begin to live their short lives as individuals. (VOY:"Survival Instinct")