My original intention was for Alexander to first learn of his powers while in the war--specifically, that flashback scene in which he was caught in an ambush and somehow survived while his comrades did not. I suppose, while writing the bio, I toyed with the idea that such self-regenerative powers manifested earlier. I'll tweak the bio to make it more clear when they first emerged (at the war). 

Sorry for not answering your question sooner. It's been a loooooooooooong day and I'm flat-out exhausted.