John Isaac Watters has long been among the most cerebral, although underappreciated, purveyors of folk music in Los Angeles, his spare meditations fraught with the fragility of his own humanity (and yours). During his 2016 residency at the Hi Hat, Watters unveiled the new collaboration Rainstorm Brother, which finds the singer-songwriter working with keyboardist-producer Tyler Chester to achieve a sound that might be described as cinematic freak-folk … or, at least, experimental and extraordinary.