Heroes 5.5 WarGame Edition - Tactical Edition.

They couldn't have come up with better names for the alternate factions than the ones they did.

It's not difficult to come up with names, even if you only draw from Scandinavian mythology/culture. What's the problem with calling them Jotunn, Aesir, or Vanir? Or Húskarl, if you want something in the style of Jarls and Thanes?

Added 12 minutes later
Here's the link to Wikipedia. On the right, you can immediately see a good set of titles that can be used instead of Earls.