Re: MA Oceania
 

If I was the only underwater nation left, I don't think I'd be too afraid to cast arcane nexus. You could always cast sea of ice before or afterwards while you build up and collect gems.

Also, doesn't MA Oceania have the best underwater units for MA? I seem to recall they have some sacred cavalry that would be pretty good for a bless.

Re: MA Oceania
 

They have sacred trident knights. They are pretty nice - good all round stats, nice health, recuperation and they are amphibious. However they are 100 gold and capitol only aswell as not being cheap resource-wise.