Well if they die fast anyway you can hardly call them immortal can you 
 
and I was talking about a whole nation of really undying immortals 

.
I think immortal units are great for flavor but insisting on a whole nation of them is just too much I'd say.
				__________________
				Want a blend of 
fantasy and 
sci-fi? Try the total conversion 
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New and different undead nation? Try 
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In for a whole new sort of game? Then try my scenario map 
 Gang Wars.