Rex Ryan looks perfectly happy as he sits in his darkened office inside the Baltimore Ravens' training complex. The wall on his left is covered with scribbled notes and diagrams of defensive packages. A video of the Indianapolis Colts, Baltimore's season-opening opponent, is projected onto the wall in front of him.

This -- the office of the defensive coordinator -- is where Ryan has wanted to be for so long. After six seasons as the Ravens' defensive line coach, he was promoted to coordinator during the offseason.

There is a great responsibility that comes with being the defensive coordinator of the Baltimore Ravens. There also is the potential for great rewards. The two men who preceded Ryan are now NFL head coaches, Marvin Lewis with the Cincinnati Bengals and Mike Nolan with the San Fransico 49ers.

The Ravens, who are celebrating their 10th season in the NFL, have built an identity as a defensive power, a reputation that was largely forged by one team, the 2000 squad that won Super Bowl XXXV on Jan. 28, 2001. That defense -- led by linebacker Ray Lewis -- gave up the fewest points (165) and fewest rushing yards (60.6 per game) over a 16-game schedule in NFL history.

Ryan, 42, is now the keeper of that tradition. His defense will be tested immediately, when the Ravens host Peyton Manning and the Indianapolis Colts -- the NFL's glamour offense -- in a nationally televised game on Sunday night.

"A lot of people are saying to me, 'Oh, the expectations, you've got to be feeling a lot of pressure,' " said Ryan, one of four significant defensive holdovers from the 2000 team, along with Lewis, linebacker Peter Boulware and cornerback Chris McAlister. "I don't feel pressure; I feel responsibility. But I'm ready to go with it. I don't have to flinch."

He has the elements needed to be successful, from an organization that is adept at finding productive players to an experienced staff of close-knit assistants. The Ravens have plenty of talent on their defense: Eight players have been to the Pro Bowl, including safety Ed Reed, the reigning NFL defensive player of the year. Ryan has learned from his father, former NFL coach Buddy Ryan, as well as from Lewis and Nolan.

"If you name the coordinators we've had, they're all outstanding coaches," Boulware said. "One thing they've known is they don't come in and scrap everything and start from the beginning. They take the good and use it, and if there's something where they think we can get better, they add a little piece to it, they add their own flavor and flair to it."

Baltimore's defense has ranked in the top six in the league in total yardage in five of the six seasons since Brian Billick became head coach. The Ravens have done that with different schemes and different personnel.

Under Marvin Lewis, the Ravens won the Super Bowl with a 4-3 defense (four linemen and three linebackers) that featured two big tackles (Sam Adams and Tony Siragusa) playing in front of the league's best defensive player (Ray Lewis). When Marvin Lewis left for the Washington Redskins in 2002, Nolan took over and installed the 3-4, which was a better fit for a defense that lost some of its bulk and experience in a salary cap purge.

Now, with Ryan in charge, the Ravens are returning to the 4-3, though they will still use some of the looks from last season's 3-4 defense. Ryan also is implementing the "46" defense that his father created for the Chicago Bears in the 1980s.

"I've always thought that players take on the personality of their coach," fourth-year defensive end Anthony Weaver said. "If you have a coach who's an aggressive play caller and wants to blitz constantly, that's what you're going to do, and the players are going to have that same reputation."

Lewis was a perfectionist; he wanted mistakes corrected at once. He yelled and screamed, and during games, he coached from the sideline so he could be in the middle of the action with his players. Nolan, on the other hand, spent game day in the coaches' box. He was analytical and, to use Billick's description, "professorial."

"Marvin was the type that if you messed up, he was going to jump on you and discipline you, but you knew he still loved you," Boulware said. "Nolan would not jump on you, but encourage you, tell you that you're better than that.

"Rex is a combination of the two. He has been around here so much that you just trust him. You trust what he says."

That trust -- which also runs from Ryan to the players -- is one reason why his transition to coordinator has been so smooth. He is liked and respected by the players, not just for his straightforward manner but also for his background and history with the franchise.

Ryan is part of NFL defensive royalty; his family owns five Super Bowl rings (Buddy won with the New York Jets in 1968 and Bears in 1985, twin brother Rob, now Oakland's defensive coordinator, won two with the New England Patriots). His coaching career spans 19 seasons, from small college football to big-time college football to the pros.

The Ravens' 2000 defensive line featured big bodies with even bigger personalities: Siragusa, Adams, Rob Burnett and Michael McCrary. The past two seasons, the line comprised undersized overachievers: Kelly Gregg, Marques Douglas (now with San Francisco) and Weaver. Yet Ryan achieved the same kind of success with both units; Baltimore's defense finished among the top three in fewest yards per carry in each of his six seasons as defensive line coach.

"The players know how much Rex has been a part of what we've done," Billick said. "I think there's a certain value they place on the fact that Rex was here with Marvin, Rex was here with Mike, so he kind of has the same history we do. He knows where we come from. He knows how to tap into the personality of what we are."

It just so happens that the Ravens' defensive personality -- the swagger, the confidence, the aggressiveness -- mirrors Ryan's. Ryan, like Lewis, will be on the sideline during games; he would not survive a game in the coaches' box, so far away from the action. "He'd be like a caged tiger," Billick said.

Ryan is proud and confident in his abilities; he points out that in his only season as Oklahoma's defensive coordinator (1998), the Sooners' defense ranked sixth in the nation despite featuring a handful of freshmen. He's affable and self-deprecating, and he's quick with a joke. During the Ravens' media clinic in May, for instance, he showed head shots of the defensive coaching staff -- except that he replaced his own picture with one of Brad Pitt. "My wife said I got better looking once I became defensive coordinator," Ryan said.

"The players like Rex," Billick said. "They like playing for Rex; they like working for Rex. They understand that Rex is pure of heart: He is about defense, he is about pressure, he is about passion, he is about winning."

"You want to give your heart out for Rex," Terrell Suggs said. "I don't know what it is about him, but I hope he never changes. That's exactly why in a heartbeat, no matter what he'll ask me to do, I'll do it. I love Rex Ryan."

Suggs is one of several players whose roles will change under Ryan. Suggs made his first Pro Bowl last season as a linebacker, but this season he will drop down on the line and play what Ryan sometimes refers to as a "rush backer," the defensive end position that Richard Dent filled so well for the Bears.

Deion Sanders, perhaps the best shutdown cornerback of all time, is being used as a nickel back, lining up in the slot and even blitzing on occasion. Safety Will Demps has lined up as an outside linebacker.

The "46" scheme is designed to free up Ray Lewis, whom Ryan says is the best player he's ever seen, and allow him to be the dominating sideline-to-sideline player that he is. During the preseason, the Ravens used the "46" on roughly a third of their defensive snaps.

"To come into camp and have my defensive coordinator say you won't be touched, I feel like a kid all over again," Lewis said during minicamp. "I don't go out and try to bash people and then get to the football. No, I get to the running back. No running back wants to face me in this league."

Four backs (Priest Holmes, Curtis Martin, Corey Dillon and Jerome Bettis) ran for more than 100 yards against Baltimore last year, and the Ravens lost three of those games (Kansas City, New England and Pittsburgh). That shocked a defense that had been so good against the run; in the previous four seasons combined, the Ravens allowed just eight 100-yard rushers (five in 2002, when Lewis was sidelined with a shoulder injury).

"I may take a beating, but I'm never going to take a beating with you running the ball down my throat," Ryan said in May. "Whatever it takes to make sure that's not going to happen, we're going to do."

No one had success running the ball against the Ravens' starting defense during the preseason. Baltimore held Atlanta's Warrick Dunn and T.J. Duckett to a combined 27 yards on eight carries, Philadelphia's Brian Westbrook to two yards on four carries, and New Orleans' Deuce McAllister to 29 yards on nine carries.

Only one touchdown was scored against Baltimore's starters in five quarters, a 51-yard pass play to Westbrook from Donovan McNabb. Opponents made a combined five trips inside the red zone against the starters with no touchdowns. Opponents had a third-down efficiency of 19 percent (3 for 16).

But that's just the preseason. Ryan knows what will be expected on Sunday against the Colts.

"The good thing is, I've been a part of all this already," Ryan said. "In our playbook, we put 'Upholding Tradition.' I think that's our job as coaches, our job as players. We talk about that Raven mind-set playing defense, and that means something to us. It means something to me."

"He is about defense . . . he is about passion, he is about winning," Coach Brian Billick says of Rex Ryan, above.