The X-Files: 10 Best Characters Who Appeared After Season One

10. Arthur Dales

While Fox Mulder is viewed as the agent closest related to the X-File, in season five's fifteenth episode, fans were introduced to Arthur Dales, and the origins of the X-Files were finally revealed in quite the interesting tale.

Arthur Dales is canonically the first person to delve into the seemingly endless pile of controversial FBI cases labeled under X, originally labeled the U-Files for "Unsolvable".

As an FBI agent who worked during the 1950s, Arthur originally worked under the House Un-American Committee, which was focused on hunting down communists or anyone that was viewed as having "UnAmerican" thoughts and feelings.

But when Arthur encountered a man with an alien spider living inside his throat, the agent's entire life changed overnight. Arthur became obsessed with that case and the secrecy that surrounded it. Even when everyone in his life constantly told Arthur to let the case go, he didn't.

That obsession helped to establish the X-Files both as a place disgraced agents go, and also the one place in the FBI that was completely focused on the truth.

Though only appearing for two episodes, Arthur is incredibly important not only to establish the origins of the X-Files in the FBI but also for serving as a kind of warning to Mulder, showing him how decades of obsession could destroy everything he held dear.