i think each kingdom should have a special ability or items. i mean, what's the point of joining if there's no advantage.
fo example:
Samurais: because they live in Santerrain, they should have a special watering can that can hold twice the amount of the original water can.
Zormites: Can swim fast on water without bomys
you can think the rest =p
__________________ "I’m starting with the man in the mirror
I’m asking him to change his ways
And no message could have been any clearer
If you wanna make the world a better place
Take a look at yourself and then make a change" -Michael Jackson (Man in the Mirror)