His plan was to wrap up the show with a mini-series, but Adult Swim evidently rejected that idea. It's not all bad news, however, since Small promised that he won't leave the series unfinished.
For those complaining about lack season 5. Was a network decision- I wanted to do it as a final big mini series. They said no. True story.— Brendon Small (@_Brendonsmall) March 14, 2015
I won't leave MF hanging though... Don't worry...— Brendon Small (@_Brendonsmall) March 14, 2015
This update comes hot on the heels of a Metalocalypse teaser being posted on Adult Swim's website. Unfortunately, the teaser consisted entirely of old clips and didn't signify anything new on the way.
.@metalinjection I have plans to service a final story & music- but not in way fans are used to. That is all I can say.— Brendon Small (@_Brendonsmall) March 13, 2015
There hasn't been a proper season of the show since 2012. In 2013, there was an hour-long rock opera special called Metalocalypse: The Doomstar Requiem.
Meanwhile, an online petition has so far raised more than 5,700 signatures in support of a new season of the show.