Music

Fiend Folio features 6 new music tracks that can play in game, made by RENREN. The album containing the soundtracks is available on RENREN's Bandcamp page.

All Soundtracks

Fiendish Foe (ft HappyHead)

This track plays when fighting a Fiend Folio boss in any main path floor, including Chapter 1, Chapter 2, Chapter 3, and Chapter 4.

Buster's Back

This track plays when fighting a Fiend Folio boss in any alternate path floor, including Chapter 1.5, Chapter 2.5, Chapter 3.5, and Chapter 4.5.

New Age Nevermore

This track plays whenever fighting any of The Modern Harbingers, which includes Meltdown and Pollution.

Maize

This track plays in the Boss Room after defeating any Fiend Folio boss.

Few and Far Between

This track plays when fighting one of the mini-bosses added in Fiend Folio, Gravedigger and Psion, that can found in Chapter 5.

Purchase Pending

This track is made up of two halves; The first half, which is just the bassline, plays while in a Crawl Space, and progresses to the second half which includes a piano while in a Black Market or in Golem's Subway.

Trivia

• RENREN has also composed a sister album to Fiend Folio known as Excelsior, which can be purchased on Bandcamp. Excelsior is also featured in a MOD made by the same developer that can be installed on Steam, which replaces all soundtracks made by Ridiculon for The Binding of Isaac: Repentance.
  • The boss theme for The Beast in the MOD Excelsior, "Forever Nevermore", uses the leitmotif of "New Age Nevermore" throughout the track.
• "Maize" uses a leitmotif found in various songs in the The Devil's Harvest OST, which includes the theme songs for floors such as Flooded Caves, Dank Depths, and the "Forest" (a floor which is a reskin and replacement of Caves).
  • The boss theme for ??? in the MOD Excelsior, "Flyboy", is a remixed and recomposed version of an unused track that was originally in the official "FiendFolio MOD" album on RenRen's Bandcamp, and also uses the same leitmotif.
• In the initial release of the MOD for The Binding of Isaac: Afterbirth+, "Fiendish Foe", "New Age Nevermore", and "Purchase Pending" were the only tracks.
• "Buster's Back" and "Maize" were added in The Reheated Update.
• "Few and Far Between" was added in The Spookaween Update.
• If both Fiend Folio and Alt Horsemen are installed, the alternate horsemen added by the latter use "New Age Nevermore" as opposed to the regular alternate path boss theme from the vanilla game, "Juggernaut".