The Reasoning's first two albums had two male singers and one female one. It started out with them equally sharing vocals, but after one of the dudes left by album 3, the other guy kind of got relegated to being back-up for the girl, and he left too, so the fourth and final album was pretty much just the girl singing.
I always thought that both of those dudes had much more interesting singing voices than her. Yes, her singing is impressive at first, especially with the dynamic of the other two, but she had a very specific way of singing that got very one-note after a while. But she was the star of the show; she shared the same last name as the band's founder so I'm guessing they were either married or siblings.