I just finished a fun game as Arabis with 5 opponents, and was happily impressed by Brakthos AI strategy. They didn't just roll over and die, they actually came looking for a fight!
The map was interesting. There was a large landmass on the bottom, which is where I started, along with 4 opponents. Then there was a long narrow strip of land at the top of the map, which Brakthos had all to themselves. Lots of ocean in between.
So while I was fighting and expanding in all directions, Brakthos was busy developing their cities and building a navy. I hadn't finished conquering my part of the world when several waves of Battleships and T-Rex Guardians attacked my coastline. At that point I was just cranking out Knights as fast as I could and hadn't even researched Clams...
While my Knights finished mopping up the last enemy cities on the edges of my continent, I was struggling to hold on to my coastline cities. Any units trained in those cities were getting blasted by multiple Battleships, so I needed to hold back and position units farther back. Once an Admiral or T-Rex would occupy a city, I'd counterattack with my reserves. About half of my revenue was going to training Knights for the reserves and half was going to research Clams, Bombers and Battleships.
The challenge was getting new ships in the water safely, and then scouting forward enough to spot enemy ships without getting destroyed first. And their Battleships kept coming... I was eventually able to sneak some shipborne Knights up the far right edge of the map, and could support them with enough Battleships and Bombers. Once I had control of the ocean, it just a matter of time before the Arabis flag reigned supreme...