OK, so this isn’t the most encouraging promo photo. But the scowly gray-haired fellow with the hat—the one who looks like he’s been hit in the face with Alice Cooper—is in fact Thomas Gabriel Fischer, better known in the world of extreme metal as Tom G. Warrior of the seminal bands Hellhammer and Celtic Frost. (If those names don’t ring a bell, I have a book to recommend.) His post-Celtic Frost group, Triptykon, has embarked on its first stateside tour, traveling with Norwegian black-metal crew 1349 and locals Yakuza (who’ve already made fans of Fischer and company on the trip). They play Bottom Lounge on Saturday night. Triptykon are second of three—they’re alternating with 1349 in the headlining slot—and Yakuza open.