a person whom one does not know or with whom one is not familiar.

Where was this strange man leading him and his sister? Wait a minute, where did he even go? Nico pulled at the hem of his sister's shirt, "Look Bia, he's gone." Bianca abruptly turned her head, her hair hitting Nico in the face. "Ow-"

He saw a strange boy holding a mighty sword come up to them from the corner of his eye. The di Angelos froze.

"My name's Percy, I'm going to take you out of here, get you somewhere safe."