Omamori Himari

Omamori Himari is about a guy named Yuuto Amakawa, who lost his parents several years ago. He has no family left, and his next door friend Rinko looks after him. Yuuto has always carried an Omamori around with him, a charm to ward off evil spirits. It was a gift to him from his grandparents. On his 16th birthday, a strange girl appears out of nowhere, but she seems to know him. Yuuto is attacked by an ayakashi, and this new girl defeats it. Her name is Himari, and she is an ayakashi as well. The Amakawa family was a family of demon hunters, and long ago one of Yuuto's ancestors chose to spare the life of an ayakashi spirit. That spirit was Himari's ancestor. Ever since that day, Himari and her lineage have pledged alliegance to the Amakawa family and to protect them from ayakashi. Since Yuuto's omamori has run out of power, Himari has shown up to fight demons for him until his powers as a demon slayer awaken. So now this cat girl samurai (apparently I have a thing for cat girls) lives with Yuuto and follows him around. She's kinda hard to miss since she dresses in traditional Japanese garb, speaks with traditional dialect and has a body so curvacious word won't do it justice. I've been reading the first volume and I have to say it's really awesome.

Ooooo this looks interesting. How many volumes and what type of anime is this?

anime-planet.com has it tagged as Ecchi, Harem, Shounen, Demons
which pretty much sums it up
it also states it is 9+ volumes long, indicating it is currently 9 volumes long but is also still an ongoing series