From the SRK KOFXIII Strategy Guide:
"In a nutshell
Art of Fighting protagonist, KOF regular, and the original Ryu clone that caused Capcom to create Dan in parody. Ryo has a moveset that should be somewhat familiar to a 'shoto' player, though Ryo cannot play a full zoning game but makes up for it with his close-range tools. Ryo has a strong set of fundamental normals with plenty of hard-hitting, cancelable pokes that beef up his grounded game. Although an executionally simple character, Ryo can deal solid damage with meter while controling both the neutral and close ranges. As such, Ryo makes for a viable character for any level of play."
Although not my favorite version of Ryo, which is Ryo KOFXI version, in this game he is still very solid, even without some mainstay specials.
Will add more stuff later but here are a couple of fun Ryo videos:
KOFXIII: Ryo Rob Tak (Art of Fighting Team)
KOF 98UM: EX-Ryo Brian Kyo Terry Eiji Tak
KOF XI: Ryo (Leader) + 2 Random