Swans should not be sounding this powerful and magnificent this late in the day. Returning from a 14-year hiatus in 2010, Michael Gira and company have defied the rock-band law of ill-considered reunions. Their latest effort, The Seer, offers two tumultuous hours of majestic mantras. Whereas ’80s-era Swans were perhaps the most nihilistic band ever, they now generate a stoic ecstasy through songs that sound as if they were recorded in the winter on mountaintops. (Neumos, 925 E Pike St, www.neumos.com, 8 pm, $25 adv, 21+)