“I just bought a red sequin strap because I am becoming a diva. Don’t even look at me.” So said the virtuoso guitarist who calls herself Kaki King at the Living Room on Saturday, where her family, friends, and a few press people had gathered to hear an unannounced show kicking off her tour in support of Dreaming of Revenge, out Tuesday. Sequin strap or no, the vibe was decidedly casual: Kaki paused tune her guitars herself, joked with bandmates, and dedicated songs to toddlers in the back of the room. But if her banter was low-key, her playing was anything but. When she wasn't singing, which was about half the time, she barked commands at her band, and she handled her instrument with fret-thumping intensity. When she did sing, it was with a newfound strength now that she's two albums into the practice. Kaki & Co. finished up with a rousing rendition of “Fashion Tattoo,” a poppy-punk anthem by German band Bubonix, whose guitarist Sara DC nodded her approval from the front table. The guitar, you see, speaks the universal language. —Lauren Salazar