Frequently, that mission is messianic or apocalyptic.
Leaders answer to no higher authority, such as an oversight board.
The group structure is hierarchical and authoritarian. Rarely will you find an open election in a cult. The group tends to be totalitarian, with elaborate rules and rituals that occupy large parts of every day. To break a rule or ignore a ritual carries the danger of expulsion from the group. The group usually presents itself as innovative and exclusive, even elitist.