I see the point about protecting against assassinations but I think they would still be effected by old age. In my test the Pan I enslaved started suffering from old age once he was a regular unit and didn't have his nature magic.
In a multiplayer game I am playing, I had taken over the home province of the enemy a few turns ago. This turn I killed his mage which had cast 2 globals and had also cast twiceborn. Checking the global enchantment screen shows the globals are still up!!
I'm not sure about the mechanics of twiceborn, the manual says the mage returns to its home province as a wight mage. I assume that since I have his home capital and that I got items off the dead mage that it is in fact dead and will not return as a wight mage; that the globals still being up is a bug.
I assume that since I have his home capital and that I got items off the dead mage that it is in fact dead and will not return as a wight mage;
You'd get the items in any case. Returning takes aways the unit before it is killed, but twiceborn and immortals drop their items in combat like usual if they are being "killed". They just cheat Death afterwards.