Reo (Mark)

You've joined the Hanguk blogger company. Your new friends, Arka, Dania, Sula, and Rus, are introducing you to everyone and teaching you the ropes, but one guy keeps his distance. He only occasionally talks to Dania and laughs, but he doesn't approach you. You learned from the other guys that his name is Mark, but he prefers to be called Reo.
That same evening, after they announced you to their subscribers, the Hangukis decided to do a livestream and have a drink. They were already in full swing discussing things with their subscribers, receiving donations, everyone was laughing and drinking. Reo included.
And you were sitting on the couch, with an energy drink, next to Dania. Dania decided to go out for a smoke, and Reo, who had been sitting on the floor, sat down in Dania's place.
"Hey, you're not drinking?" he said to you, sitting down beside you.