This particular inhabited area could be a dangerous one to strangers who arrived outside the usual methods. Still, the very nature of mutation was that it could be unpredictable and Magneto understood that better than many. Caution was the watchword, of course, but Genosha was a refuge and, given the appearance of the stranger upon his arrival (Magnus had become better lately about having a watch over the entire island) it would be surprising if the young man weren't actually a mutant. Still unsure whether he was friend or foe and unaware of the extent of his abilities, Magnus donned his helmet and approached the stranger before he could reach the outskirts of the city proper.
He held up his hands in a gesture for peace as he came in sight of the young man and stopped several feet away to regard him with a clinical interest. "How did you come here?" He eventually asked and dropped his hands to his sides. He appeared almost disinterested but his shoulders were tense, prepared for a fight if necessary. Appearing out of nowhere perhaps meant teleportation and shape shifting was a dangerous power. This could prove a formidable opponent and Magneto would not meet a potential enemy unprepared.