Your main character is fascinating, but I would prefer that he makes some more references to his past in this. A short summary in the author's note doesn't do it justice. Also, since this is written from his point of view and he seems well educated and enjoys intelligent discussions, you may want to explain how he became so in a band of mercenaries. On the subject of his dream-stone: does this perhaps end up in the pommel of a dagger that one Artemis Entreri comes into possession of? It's properties are exactly the same, although it has never been explained what gives his dagger its life-absorbing properties.