The “Children of Empire,” ZE:A channeled their inner phantoms for their comeback “The Ghost of Wind,” a tribute to the long running Broadway play Phantom of the Opera.

Fans of ZE:A were treated to the first look of the music video for “The Ghost of Wind” on August 8, 2013 in Gangnam, South Korea during a showcase just before the new album Illusion was released worldwide. The song is reminiscent of Broadway, incorporating a 14-person orchestra and male tenors. 

The group's comeback was delayed to give leader Lee Hoo time to heal after he slipped while filming a variety show. In that time, ZE:A treated fans to the pre-release single "Step by Step" on July 31, 2013—a bright acoustic guitar song written and composed by the group's rapper and lead vocalist Kevin. It was included on their first mini-album Illusion and promoted alongside the title track, "The Ghost of Wind."

Matching the theoretical theme of the song, the music video for “The Ghost of Wind'' replicates scenes from the Phantom of the Opera, using grayscale set designs and muted colored props. Recreating scenes from Phantom’s musical numbers “The Mirror” and “I Remember,” the members play the piano and sing longingly into a mirror with a woman in view behind them. As the song tells the story of one being like a ghost to the person they love, viewers follow the members dressed in all black through empty rooms and alleys, standing just out of reach of a woman dressed in all white, similar to Phantom’s female lead Christine. 

ZE:A debuted the live performances of “Step by Step” and "The Ghost of Wind" on Music Bank the same day as the album release, August 9, 2013. They performed in white tailcoats with blue paisley designs on the back, adding a ghostly effect to the choreography. The set even incorporated chandeliers similar to the iconic piece used in Phantom of the Opera. The “Step by Step” performance offered a brighter image of ZE:A, contrasting the darker concept in “The Ghost of Wind.”' It highlights the members’ vocal abilities with a more subdued dance performance that incorporates microphone stands. 

“The Ghost of Wind” became ZE:A’s highest charting song, reaching No. 21 on the Gaon Digital Song Chart the week after release. Dispatch also ranked the group at No. 14 for top boy groups of 2013. After about a month of promotions, the group said goodbye to their fans on music shows, making heart signs during each close up. But ZE:A didn’t hang up their tailcoats just yet: they brought back the ghostly costumes for the year-end holiday shows, SBS Chuseok Special and SBS Gayo Daejun. 

2013 marked a lot of firsts for ZE:A, including their first solo concert in South Korea. On November 23, they took the stage at the SK Olympic Handball Gymnasium for their concert Illusionist. They wrapped up the year of Illusion by taking their performances on the road, touring in Japan and Malaysia.