kendo is japanese fencing utilizing the shina (bamboo sword)
kenjustu and the old version of japanese fencing utilizing the bokken, (wood sword)
kempo- there are several types depending upon the country. it is also a very generic term. it can mean karate in okinawa, there is also chinese kempo, korean kempo, american kempo and all are diffrent, it represents a group of styles and not a single style
bujinkan- is an organization and not a martial art