Zao Saga is a Manga/Manhwa/Manhua in english language, ACTION series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Being the only and single kid who doesn't have a special power to his name of Zao family among the country ruling clans, Taichiro obtains the strongest ancestor Gaki's power. The families that feel the fear of unmaintainable power kicks Zao family out of the union and sends assassins to make them disappear.