Six orcs. GIN MOTHERFUCKER
Let's get this out of the way now: Ethnos has no business being as good as it is.
More timely reviews suggested that Ethnos' aesthetic doesn't match the gameplay, and I'd agree with that. It has a pretty gloomy look for something that's basically Dragonlance Rummy. The dark air gives the game a sense that you're doing deadly battle over the territory on the board, but that's not really a feel to which the mechanics lend themselves. It's a territory control game, but you're only fighting with numbers, not the people or creatures that form your armies.
Each turn you can draw a card from those face up on the table, draw one blind from the deck, or play a set and hopefully add to your hold on a territory. Every card has a fantasy race, and a color associated with one of the territories on the board. By playing a set of cards that match in either color or race, you can add a token to the territory of that set's leader, the card you play on top. In addition, each race has a special ability, and you can use that ability if the leader of a set is a member of that race.
There are some catches, though, that turn this from "WTF is this" to "Wow, this is pretty good". First, a set can be as small as one card, but in order to add a token to the appropriate territory, the set has to be bigger than the number of tokens you already have there (ie. only a set of three or more can add a token where you already have two). Second, larger sets are worth more bonus points, so as the game continues you're doubly encouraged to build big sets so you gain more control over a territory and get bigger bonuses.
Working at cross-purposes with this, however, is that when you play a set, you have to discard your hand into the face up tableau. You can try and save up for a bigger set, but if you keep getting mismatched cards, you can't just hang on to them for a future turn--you have to discard them for your opponents to take. Even if you were able to get most of them back, you're taking extra turns picking them up a second time, and there's a good chance you can't afford to use too much time doing that.
The game goes through three ages, with increasing (but randomized) numbers of points available for holding each territory at the end of each age. The points for early ages aren't merely gone after they're scored, either; the score for holding a territory at the end of the first age also acts as the second-place reward for that territory in the second age and the third-place reward in the third. Therefore, you don't just consider how hard to go after a territory; when you do it matters as well.
There are twelve fantasy races; six are used in a normal game, five in a three-player game. Each of the races has a special ability that makes sense in the confines of the game (e.g. one race lets you put a token in any territory, one lets you keep a certain number of cards in your hand, and so on), but a couple also add mechanics that add entirely separate pieces. The giants, for example, give a bonus to the first person to have a giant leader in a set, then that bonus again to whoever plays a larger set with a giant leader, and so on. At the end of a round, if someone is holding the giant... piece, they get an extra bonus. Orcs let you create an entirely different type of set over multiple rounds for extra bonus points. It's the kind of thing that would get hammered if they did it poorly, but they didn't, and these ideas work out well.
There are people working on reskins of the game, and those might be more fun to look at, but you don't need them to make this worth playing. Play with four or more if you can for the full experience; three people only play through two ages, and it leaves the game feeling like it's not quite done.
Score: Twenty horny halflings out of twenty-four.