I think Corylea makes very good points. It is very unlikely that he was a product of the Salamandra's experiments--not enough time. It definitely has to be a witcher from one of the other two schools and who knows what's going on with them. That witcher could of just gone rogue and joined some assassin guild or something. Or, maybe one of the other schools has forseen a major problem with the politcal structure that had manifested and had no other choice but to try and dissolve the treatise that had just been established. Definitely can't wait for #2