Shadowmere is an online text-based strategy game. You are the king of a kingdom of one of the seventeen races in the game, and your goal is to help your kingdom grow. The community is very friendly, however don't be surprised if you are attacked. But don't worry, unless you are actively trying to sabotage yourself, it is always possible to recover, and usually you will be better off than before.
Okay, so this sounds like an advertisement. Well, it is, sort of. I have been playing on-and-off for the past seven years, and I still enjoy it immensely. Be sure to read the help guides before starting, though, and remember that it is easiest to begin as a Wood Elf. Good luck!
But, for the more experienced players, I thought this might be useful: It is a Shadowmere calculator built into a Microsoft Excel spreadsheet, with a focus on offense. It attempts to add up your damage and absorption, and the damage and absorption of your enemy, and decide whether you will win a military attack. Beyond that, it will also help you decide whether it is worth trying to destroy some of his buildings by telling you how many extra Outpost, Guard Tower, Barracks, and Castle pieces he has (those not housing or protecting troops).