The children are probably drawn to him because he looks like a magician or a wizard... which he is. Of course, Mary doesn't know that. She just thinks it's cute that all of the children want to spend time with him. Children don't naturally flock to her, as she tends to come off as cold initially, but seeing the man with them makes her feel a pang of longing for her son back home.

After the children run off, Mary approaches with a smile. She hasn't seen the man around Asgard before, which means that he must be a new arrival. As one of Tyr's ambassadors, she'd like to at least make contact with him.

"I can't say any of us know what the runes mean either, but apparently they are important to the natives. Hopefully drawing them won't result in something strange happening."

Asgard tends to be a place where strange things happen more or less regularly.