So, is Aerhien's immortality the result of something like a quantum suicide? :)

This is a good piece of SF, but it suffers from a severe case of an ailment common to the genre, which is that someone who's never heard of X (in this case the many-worlds interpretation of quantum mechanics and the anthropic principle) isn't going to have a clue what the hell you're talking about. Additionally, it's kinda hard to tell at first what elements of the story are made up (magic words, dust, summoning, etc) and what we're supposed to connect up with something from science (I would have figured out ahntharhapik principle eventually, probably).