In the second week, I captured an orange city, and he found a neutral fortress somewhere. I had to slow down and eliminate him; he was getting annoying.
A capital city (Conflux) of Brown appeared nearby, but I was one move short of capturing an empty city with free units.
In the end, I got frustrated, attacked with my main hero, and found a well-defended city that had been upgraded to a Castle. Three towers wiped out all my melee units, Gogs, and Dogs.
I give up, gg.
Thanks for the game.