Question: What was the companion piece that Poe's brother published?

Passages:
<P2-S0> A God in Ruins the ninth novel by Kate Atkinson was published in 2015. <P2-S1>  The main character, Teddy Todd is the younger brother of Ursula Todd, the protagonist in Atkinson's 2013 novel, Life After Life. <P2-S2>  Atkinson calls it the "companion piece" rather than a sequel to the earlier novel. <P2-S3>  Both books are about World War II. <P2-S4>  It won the Costa Book Award for Novel in 2015. House of Leaves is the debut novel by American author Mark Z. Danielewski, published in March 2000 by Pantheon Books.  A bestseller, it has been translated into a number of languages, and is followed by a companion piece, "The Whalestoe Letters". Marisha Anne Chamberlain (born January 6, 1952) is an American writer.  Her most recent work, the libretto for "Mortals & Angels", a collaboration with American composer Carol Barnett, premiered at Carnegie Hall in 2016, a companion piece to their widely produced collaborative piece, "The World Beloved: A Bluegrass Mass".  Her stage plays, both original works and adaptations are widely produced.  Her debut novel, "The Rose Variations", was published by Soho Press in 2009.  Her play, "Scheherazade", won the Dramatists Guild/CBS National Award, and in her screenplay version, played on public television across the country, and was screened at the British Film Institute Festival in the category of Best of American Public Television. The Spectre Knight is a one-act "fanciful operetta" with a libretto by James Albery and music by Alfred Cellier.  It was first performed on 9 February 1878 at the Opera Comique by the Comedy Opera Company as a companion piece to "The Sorcerer".  The piece continued to run until 23 March 1878 and was revived by the company from 28 May 1878 to 10 August 1878 as a companion piece to "H.M.S. Pinafore".  The piece had a run in New York in 1880 and was toured in Britain and America. Battle of the Nations is a World War I era song released in 1915.  E.T. Paull wrote the music and lyrics for the piece.  The song was published by E.T. Paull Music Co. of New York, New York.  On the cover, there is a colorful depiction of a battle scene.  On the borders are seals from different countries, including Japan, Belgium, France, and Germany.  The song is a "companion piece to the celebrated Napoleon's last charge descriptive march," as stated on the cover. Haunted is the second album by American singer-songwriter Poe, released in 2000 (see 2000 in music) after a five-year hiatus from her debut album "Hello" in 1995.  The self-produced album was created as a tribute to her father, and counterpart to her brother Mark Z. Danielewski's novel "House of Leaves". Uncle Samuel is a one-act comic opera with a libretto by Arthur Law and music by George Grossmith.  It was first produced at the Opera Comique on 3 May 1881 to 8 October 1881, as companion piece to "Patience".  The piece also toured from December 1887 to June 1888 as a companion piece to "H.M.S. Pinafore". <P1-S0> The Padlock is a two-act 'afterpiece' opera by Charles Dibdin. <P1-S1>  The text was by Isaac Bickerstaffe. <P1-S2>  It debuted in 1768 at the Drury Lane Theatre in London as a companion piece to "The Earl of Warwick". <P1-S3>  It partnered other plays before a run of six performances in tandem with "The Fatal Discovery" by John Home. <P1-S4>  "The Padlock" was a success, largely due to Dibdin's portrayal of Mungo, a blackface caricature of a black servant from the West Indies. <P1-S5>  The company took the production to the United States the next year, where a portrayal by Lewis Hallam, Jr. as Mungo met with even greater accolades. <P1-S6>  The libretto was first published in London in 1768 (?) <P1-S7>  and in Dublin in 1775. <P1-S8>  The play remained in regular circulation in the U.S. as late as 1843. <P1-S9>  It was revived by the Old Vic Company in London and on tour in the UK in 1979 in a new orchestration by Don Fraser and played in a double-bill with Garrick's "Miss In Her Teens". <P1-S10>  The role of Mungo was, again, played by a white actor. <P1-S11>  Opera Theatre of Chicago have recently revived the piece (2007?) <P1-S12>  where, it would seem, the role of Mungo was changed to that of an Irish servant. The Carp is a one-act comic opera (styled "a whimsicality") with a libretto by Frank Desprez and music by Alfred Cellier.  It was first produced at the Savoy Theatre from 13 February 1886 to 19 January 1887, as a companion piece to "The Mikado".  It was then revived as companion to "Ruddigore" from 21 February 1887 to 5 November 1887.  The piece also toured throughout 1888. "A Predicament" is a humorous short story by Edgar Allan Poe, usually combined with its companion piece "How to Write a Blackwood Article."  It was originally titled "The Scythe of Time".  The paired stories parody the Gothic sensation tale, popular in England and America since the early 19th century.

Supporting sentences:
 The self-produced album was created as a tribute to her father, and counterpart to her brother Mark Z. Danielewski's novel "House of Leaves".  A bestseller, it has been translated into a number of languages, and is followed by a companion piece, "The Whalestoe Letters".