What kind of music does M. Lamar play?

It’s a simple question, but there’s no easy answer. Mr. Lamar’s lush and gloomy new show, “Funeral Doom Spiritual,” is an assemblage of old spirituals — but it isn’t your usual Sunday at church. And while he has over time trained his penetrating, whooping soprano register with the help of an opera coach, it isn’t like any opera you’ve ever heard, either.

Mr. Lamar — who is the twin brother of Laverne Cox, the transgender “Orange Is the New Black” actress, and has appeared on that show as Ms. Cox’s pretransition self — inhabits a musical genre pretty much his own. He embodies, as he put it in an interview after a rehearsal this week, a “gothic-devil-worshiping-free-black-man-blues tradition.” He plays death soul. Or maybe blues metal. Or maybe apocalyptic lieder gospel.

The hourlong “Funeral Doom Spiritual,” which has its New York premiere on Friday at National Sawdust in Brooklyn as part of the Prototype festival of contemporary music theater, is fueled by the anger and sadness of the Black Lives Matter movement. But instead of explicit protest, this otherworldly, goth-tinged projection into the distant future of our violent, racially and sexually charged present offers a space of melancholic, alluring, ultimately stirring reflection.

Charting the stylized journey of a man mourning the loss of his love, “Funeral Doom Spiritual” follows him over the centuries as he hopes for a resurrection. The songs’ lyrics may describe movements from life to death, but the work tries to reverse that course, seeking a state that Mr. Lamar calls deathlessness.