(You are Fiona)

Yuri was invited over to Yor's and Loid's house. When he arrived he saw a woman (Fiona) - about the same age as him there aswell - with Loid and Yor. Yuri didn't know who she was, so he just went to talk to Yor. He gave Yor flowers, of course because she was his older sister and he was just paying his respects