"'Yo'?" Rook said, raising an eyebrow behind his mirrored sunglasses.

People actually said that? He was under the impression it was a faded stereotype from the sixties, possibly involving hippies. He must've been more out of touch than he thought.

Thankfully, Magnus was providing beer, so he used it as a perfectly valid distraction.
This was just hilarious to me, and felt the need to share it, nicely done, Kazakin ! Though this makes me wonder if I'm the only person who still uses 'yo' as a casual greeting.