Thalmarkin has hardly opposed Ar Agyr's might.
I'm guessing you can have fun in pretty much every realm if you commit your character. Not all realms have as much nobles and of course in those smaller realms things are not as vibrant as in the bigger ones but they need other committed characters all the more.
Right now this is the situation:
Thalmarkin, Ar Agyr, Old Grehk, Spearhold and Gotland are fighting on the side of the King of Kings.
Nothoi and Caelum are actively opposing those realms. The Vales just had a little civil war going which the Ivory Vale has won. They were both opposing the King of Kings though. Riombara have lowered their relation with the Ivory Vale as a result. Riombara of course also opposes the King of Kings but have not been seen on a battlefield for months, in stead providing financial aid afaik.
Fronen has surrendered to the King of Kings but are not participating in the war.
The main fronts are Caelum and Spearhold, which also got a bit of an independent war going on and Old Grehk and Nothoi.