Ryuuga merely made a cameo in the 아니메 when Sakyo talked about him. It was implied that Sakyo had met Ryuuga in person, but they never specified when. This made it unclear whether Sakyo met Ryuuga before 또는 after Nemesis was defeated and Ryuuga's supposed "death".
In the 망가 though, it was confirmed that Sakyo did, in fact, meet Ryuuga after the defeat of Nemesis. Ryuuga appears in the 2nd special chapter where he and Sakyo battle in the mountains.
