Ryo Sakazaki , son of Takuma and apparently dating King according to the storyline.
As much as I like calling K9999's general gameplay an advancing defense, its definitely no match for Ryo's.
Ryo has been described by many as 2002's 'tank' character(Maxima as runner up) due to his generally poor mobility, no 'good' cross up moves, command throws or projectiles, but high priority special moves and the ever popular 'Ryo parry'.
As far as I know, his basic combos can vary from:
-Close C, Forward A
-Close C,
+ P-Stand A, crouch A, crouch B, Stand B,
+ Ketc...
However, his poke combo is surprising, I believe he is the only character in 2002 who can link a heavy(non command move) attack after a light poke(discounting cross ups) giving him his:
-Crouch B, Crouch C,
+ P
His ranbu DM(rush) , at proper distance will go through fireballs and is quick to come out.... although, obviously his Haoshokouken(projectile) will also pierce projectiles and hurt the 'user'
His forward A overhead has good priority and comes out at fairly decent speed, if you have quick hands you can link it into a fairly short, but effective BC combo, I don't have very quick hands so I've only done:
-Forward A , MAX mode activation, Far C,
+ K Which isn't that bad to land some good damage from an overhead.
His
+ P will nullify non DM projectiles(except maybe Leona's) and has high priority, it can stop early jumps, while his 
+ P, has various frames of invincibility, not to mention his parry into F,B,F + P will also stop 'late' jump ins.Despite having a good defense and a rather diverse moveset, Ryo seems to have trouble fighting characters such as Billy Kane, and to a lesser extent, Leona.
Anyway, Ryo's gameplay is fairly rigid , it doesn't involve jumping around like a madman or relying on 'the combo' to win the match(barring his HSDM at times), a sleek and smooth advancing defense is more his style.
If I had to put a specific tier to Ryo, I'd say, upper middle tier, just *BARELY* outside of the higher tier area, this due to his 'insane' defensive game, high priority special moves and great poke combo. He lacks a more 'profound' offensive game, but it would be insane if he had greater offense with his already strong(est) defense.
And so forth...
It's been a popular question that no one can answer that surely yet I think.
, after a million tries though, and only about 3 times it has come out, meh who cares. The feeling you get when you do Ryo's SDM: priceless 8)
+ a). AUCH!! 
