User blog comment:SayuriDarling/The Sword of Summer Official Discussion/@comment-5471249-20151020221715/@comment-26379358-20151021062847

It depends on how strange they consider things. Magnus was not surprised when a severed head was removed from a bag after two days in Valhalla. Then  again Annabeth has saved the world twice, though not nine of them so I don't know how to score that. Plus the whole revealing that he is really dead and is now an immortal viking warrior with a magic flying talking sword may be the breaking point. And greek myths are taught in schools, at least at an early level so Magnus would not be as caught off guard as Annabeth who probably has no clue about Norse myths. So I'd give it to Magnus due to him being in the stranger mythology.