Character Factor

Characters are in two groups; there is also a quick check page for each season for fact checking purposes.

Main Characters
 are just what they sound like; the characters seen each week, or at least most weeks of the series.

Recurring Characters
 are guest characters seen in at least two episodes

Character Information by episode
 character development as listed on individual episode pages, for those times you just need a quick check.

Character pages do contain spoilers for the series.