Marika Willkarah (played by Bertila Damas) was a member of Seven's unimatrix and a former Borg drone designated as Three of Nine, Auxiliary Processor of Unimatrix Zero One.
Willkarah is a Bajoran and formerly served aboard the USS Excelsior.
After temporarily being separated from Borg collective by the crash of their ship, Willkarah, along with three other drones - Lansor, 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. Willkarah 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. Willkarah and the other two agreed to accept this shortened life as the cost for true freedom. Willkarah decided to live the remainder of her life aboard Voyager. (VOY:"Survival Instinct")