Niklas Almqvist (born 26 January 1977), better known by his stage name Nicholaus Arson, is the lead guitarist and backup vocalist of the Swedish garage rock band The Hives, of which his brother Howlin' Pelle is the lead singer.

It was revealed in NME that Randy Fitzsimmons is a registered pseudonym belonging to Arson.

[1] This has led many to believe that Randy Fitzsimmons is in fact a myth, and that it is Arson who writes the songs.

His guitars often reflect the outfits of the band with different combos of black and white finishes and pickguards.

Along with Vigilante Carlstroem and Dr. Matt Destruction, Arson uses white Hiwatt amplifiers.