And somehow, I don't think it is a nice concept to kill a sovereign with a powerful end game spell: want to kill a sovereign? You just need to raise a volcano under its feet...
Having an immortal unit that can die reminds me Highlander: immortal beings that are fighting themselves and can only die if their head is cut from their body. Maybe we need something like that for sovereigns: they can only be killed in specific conditions. If conditions are not met and the sovereign hit points drop to 0 in a combat, after the combat has ended, the sovereign keeps 1 hit points and gain no XP from the combat.
I was really expecting more suggestions along these lines. While I like my idea better, I feel that having sovereigns be indestructable to all but "elite" level troops or "tier 4 spells" or higher is an acceptable solution. (the quotes are just examples, obviously. I'm not aware of any tier system in the magic or anything like that. Just hypothesis. I also don't think a volcano should be auto-kill the way it was at PAX, but thats likely in part because I had a hard-on for volcanologist documenteries as a kid and so I've seen people do stuff like run across liquid magma in plain steal-toed boots. Part of it is my opinion on the subject relates to balance and scope of magic spells, but we'll cross that river when it comes.)
A grey area to me was Highlander death by beheading. When I was a kid I thought it was any beheading, but later I was told it had to be a Highlander that did it (special effects and lightning show, I guess, is a requirement), and not just anybody who happens to bring a sharp heavy blade to their neck. So I would say it is also reasonable if another channeler, powerful hero, or immortal monster has to be present to channel the immortality out of the sovereign. But likely this would mean those writing those books they've planned might have to change a few things if it isn't already how it worked.
Your sov gets experiance from all units in empire.
Lol... I'm pretty sure thats a bug resulting from combat not really being in yet.
(on volcanoes: earthquakes, mudslides, and falling airborn ash are what ACTUALLY kill people. Sometimes Pyroclastic flows, but you have to be rather unlucky to actually be hit by one of those since they don't blanket the entire surrounding country side or anything like that. so the actual death rate to them is fairly low. I feel volcanoes should be more about destroying economies and wrecking havok than actually killing people. There are much flashier, and more reasonable, ways that FIRE magic could wipe out entire armies or cities. That being said, USUALLY, people know ahead of time they should move before a volcano erupts, since non-magical ones smoke a bit 1st... so I'm going to stop typing. Another word from what Wintersong has dubbed "Landisaurus Geographic")