Shoot himself in the chest or something? A bullet in the heart would kill you damn fast.
Jump off a building or something?
The idea isn't much different from the werewolves from Darrren Shans Demonata series. But the civil war setting sounds interesting
It's difficult to write a good plot twist. Unless you are very clever you will probably **** it up. Don't try it unless you have a great idea....
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