Are there any plans to make a sixth installment in the Heroes series?

Well, I wouldn't say so. The upcoming Disciples 3 promises to have a more muted color palette. I've seen the screenshots, and I personally like it. And even if you compare the zombies from "Dark Messiah" to the zombies from the 5th installment... Okay, let's not start that old conversation, especially since it's off-topic. But I still hope that the 6th installment will have darker tones and truly impressive demons, undead, and evil, ugly orcs, like in Tolkien's works. And I hope the 6th installment will be rated at least 16+, due to the creatures and some brutality.