I mentioned that he might want to consider doing minimalist covers instead of the characters in environments covers he has mocked up. This way, the bottom half of each book stays the same with each installment, except for the title changing. And the upper portion has a variation of the helmet each time. Brilliant!
Just a mock-up, I don't have rights to the helmet I lifted from the internet. And I'm sure Grumpy would point out that purple isn't the same as scarlet... I'm just throwing my idea out there.