Never rarely means never in the music world, and nearly five years after Slayer — one of the greatest metal bands in history — officially disbanded, they’re reuniting for two festival dates this fall, and seemingly possibly more.

The two dates announced so far are Chicago’s Riot Fest on Sept. 22 and the Louder Than Life festival in Louisville, Kentucky five days later. The former is billed as the band’s “exclusive Midwestern performance,” which would seem to leave open the possibility for more dates to be added. (With the exception of Led Zeppelin, major bands rarely reunite for just one or two concerts.)

“Nothing compares to the 90 minutes when we’re on stage playing live, sharing that intense energy with our fans,” said vocalist/bassist Tom Araya in the official announcement, “and to be honest, we have missed that.” Guitarist Kerry King added, “Have I missed playing live? Absolutely. Slayer means a lot to our fans; they mean a lot to us. It will be five years since we have seen them.”

The group — founding members Araya and King with former Exodus members Paul Bostaph (drums) and Gary Holt (guitars) — last performed together in November 2019 at the close of their “Final World Tour.”

The news does come as a surprise, as just earlier this month King unveiled a new, eponymous band with Bostaph and former Death Angel singer Mark Osegueda, and cast doubt on a Slayer reunion. “I can pretty much a hundred percent say no because I have a new outlet, and it’s not Slayer, but it sounds like Slayer,” he told Rolling Stone.

Slayer was formed in 1981 by King and late guitarist Jeff Hanneman in Huntington Park, south of Los Angeles, who soon were joined by Araya and original drummer Dave Lombardo, the latter of whom has left and rejoined the band several times. Along with Megadeth and Anthrax, the group were part of the second wave of thrash and speed metal that quickly followed in Metallica’s wake, and quickly became renowned for the speed and fire of their playing and their ultra-graphic lyrics.

Both qualities attracted producer Rick Rubin, who grew up on hard rock but was a multiplatinum hip-hop producer for LL Cool J and Run-DMC, and he soon signed them to Def Jam Records; King actually appears on the Beastie Boys’ Rubin-produced 1986 breakthrough debut album, “Licensed to Ill,” contributing the “frozen metal” guitar solo to “No Sleep Til Brooklyn.” The group’s three Rubin-produced albums — “Reign in Blood,” “South of Heaven” and “Seasons in the Abyss” — are among the finest in metal history.

The group continued through the following decades — both with and without Lombardo, one of the best and fastest drummers of his generation; Hanneman died in 2013 of liver failure after a long battle with alcoholism — but those three albums truly made their mark on successive generations of hard rock musicians.