Demon have been going on for countless years! They never really disbanded as per se, but deaths, tragedies and ever changing line-ups, that however released surprisingly consistent albums by the way, necessitated some periods of inactivity along their more than 30 yearlong semblance of a career.
 

Grave Digger have being going on since the early 80s, faltering ever slightly along the way and maybe sometimes taking a year or two off, but they have pretty much been rather consistent in their output both in terms of quantity as well as quality, as with the exception of one or two albums, the listener, pretty much knew what he was gonna get.
 

Helstar, were always one of America’s better straightforward power metal bands and did release a bunch of pretty seminal albums through much of the 80s, narrowly missing the goal of worldwide domination. Still many of them albums they released back then are considered cult classics today.
 
Now, much of the 90s was spent in hibernation, with only one album being released, with lineup changes and with the band actually breaking up and it took them some 10 years to find the road back into the studio while in the meantime, the members tried to re-establish their friendship and chemistry. Fortunately it all worked out, and the band returned, stronger than ever releasing a string of worthy albums that added to their 80s legacy.