Why does xigbar see xion as ven in kingdom hearts 358 2 days

Xigbar sees Xion as Ven because in the past, Xigbar or Braig has seen Ven, and because Xion's appearance changes depending on the viewer's relationship with any of the people connected to her, Xigbar's view of Xion is Ven. also i think the reason xion has a memory or relationship is because in Birth by Sleep Ven goes to destiny island and meets sora, and as you should know Xion has Sora's memorys