Ga-Rei-Zero

its been a while since i saw this, but it stuck in my mind as one of the better animes I've seen recently (and I've seen heaps)...note: i think this is based on a manga or game, but I've neither read it or played it (whichever)...

the story is not told in a linear fashion, so we see currents events spliced with earlier times and it can get confusing...essentially, these 2 'sisters' have incredible martial arts skills, magic type powers and have demon infused blades/familiars n stuff, and they help the government destroy monsters...but things go pear-shaped...

its bloody and violent and not really for kids...i liked it, and id like to see a second series to clarify some unanswered questions...