From the nostalgic and scene setting intro of “Toronto’s Window” to the groovy “1999,” The 13-track debut album gives fans a look inside the head (and heart) of one of K-Pop’s brightest stars.

Prior to The Firstfruit, Mark released a music video for the song “Fraktsiya,” featuring Youngji. In the music video, he and Youngji play spies, with nods to the Men in Black series. In the “1999” ...