fandamentalist
 n.— «Fandamentalists. (noun, pl.); fans who violently believe the only valid interpretation of any entertainment source is a dogmatic adherence to their favorite version of that source. Any change to the smallest detail is inherently unacceptable (see also “heresy”) and met with frantic scorn.» —“Fandamentalism” by John Rogers Kung Fu Monkey Dec. 8, 2004. (source: Double-Tongued Dictionary)