Roswell Conspiracies: Aliens, Myths and Legends (1999)

A group of allied intelligence agents discover that extraterrestrial beings arrived on Earth centuries ago and have been thriving through the exploitation of humans. Believed to be the origins of many of the creatures humans know from myth, folklore and legends, including vampires and werewolves, the group discovers that these aliens have now formed a sinister cadre bent on taking over the world for themselves. In response, the agents form a top-secret multinational agency known as The Global Alliance, charged with protecting the world from the alien threat and keeping it a secret from the public at any cost.