Guy was home, and indeed by the door only due to accident. He had been attempting to take the pictures of his family down in the living room, not wanting Sirius Black to feel imposed upon by them, and honestly not wanting to discuss his family situation with the roommate. Sirius's entire history left a bad taste in Guy's mouth, and he'd been so absorbed that he had almost missed the sounds of Gellert at the door. He paused, looking out the window, and recognized the man at once from the picture of him that had been kept on the mantel at home during his childhood. He straightened up, looking around the his space and noting that it was neat, that he was certain Sirius was out, and that they could easily go up to his room without any issues. His hand met the door, he opened it, and he nodded his head in a polite and curt manner.
Dressed well in gray slacks, a white collared shirt, and a dusty purple waistcoat, he had not yet acclimated to the fashions that were most popular there. He had not stopped slicking his hair back, or shaving with a straight edge, or wearing his pocket watch with pride. His sleeves had been rolled up while cleaning, his inner arm showing the scarring of a very early and painfully given dark mark- not the clean ink of the 80's, but the burns of the earlier eras.
"Mr. Grindelwald," he said, hiding his Irish accent well. "Please, come in."