Perhaps: one of a band. Obsolete.

A member of a league; in reference to French History, a member or adherent of the League formed against the Huguenots in the reign of Henry III…

= combiner, n. rare.

He who or that which joins in association; a confederate, companion; a member of an association.

One who combines, a confederate. Obsolete.

spec. A member of a combination; a confederate, associate, leaguer, conspirator. (Chiefly plural.)

Each of the parties to a covenant or treaty; (later) spec. an ally bound by treaty. Now chiefly historical.

A person who or thing which establishes a federation; (also) a member of a federation. Formerly also: †one who makes a treaty or covenant (obsolete).

A party to or member of a league.

= leagueist, n.

A person who actively participates in the activities of a group. Also (chiefly Marketing): a person who derives happiness or satisfaction from…