[7] The songs "Reaper" and "House on Fire" were confirmed as the seventh and eighth tracks, respectively, on the marquee of Webster Hall in Manhattan, New York City, on 6 January.

[15] At a length of 3 minutes and 38 seconds,[16] it was written by Sia, Kanye West, Noah Goldstein, 88-Keys, and Dom $olo, with the latter four handling production alongside Jesse Shatkin and Jake Sinclair.

[18] In her review of This Is Acting for Vulture, Lindsay Zoladz named "Reaper" as one of the album's best songs, calling it "a feel-good ode to cheating death".

[14] Laurence Day of The Line of Best Fit opined that although the lyrics are "wounded and vulnerable", the song is an "endearingly optimistic track", likening its belying of the "gravity of the subject at hand" to that in Sia's "Chandelier".

[19] Writing for The Arts Desk, Katie Colombus described "Reaper" as a "huge life [anthem] that celebrate[s] every breath you are able to take",[20] and Soul Bounce writer B. Cakes called the song "oddly-inspiring" and "jaunty".

[22] In 2017, staff of Billboard ranked the song as one of the best "deep cuts" by 21st century popstars, describing it as a "rumbling anthem" which "is a welcome dose of 'not today' attitude".