It's hard to imagine a good mix between the two. They're totally different. It's like trying to find a good mix between hamburgers and chocolate. Instead i'd focus on either one or the other, and let the remaining one add a non-essential but noticeable influence without becoming literally incorporated into the concept. Like if it's a viking, then just leave it at that, and create a nice costume that fits in with the viking era but allow some of the influences like symbols and weapons to be influenced by the power ranger characters. It will be a much more natural fit in the end. Right now it's easy to tell that you're just forcing the two concepts together, especially due to the colors. What do you think?