Marvin Lewis designed the blueprint of the Ravens' present-day defense and linebacker Ray Lewis gave the team its work ethic, but it was Rex Ryan who had the distinct attitude that is still prevalent to this day.
Ryan, 53, in his second season as the Buffalo Bills' coach, will be in town Sunday for the 2016 season opener against the Ravens at M&T Bank Stadium. It's a homecoming for Ryan, the Ravens' assistant coach and then defensive coordinator from 1999-2008.
"What he taught personally is just how to play Ravens football," said Pro Bowl outside linebacker Terrell Suggs, one of only a handful of players left over from the Ryan years. "Some people will always be Ravens; Rex is one of them.
"... We know with Rex what his philosophy is and what he brings to the table – basically how he likes to play football. It's good to actually play against him."
It's been eight years since Ryan roamed the Ravens sideline, but he hasn't changed much. He takes the game seriously, but never to the point where he can't have fun, especially laughing at himself.
The bravado is still there, which made him a perfect fit as the New York Jets' coach from 2009-14 (the Ravens won all three meetings with Ryan's Jets during that period). He has always been a forgiving type, which is why his rosters often have several players who have been on some city's police blotter.
But the name Ryan is synonymous with the famed "46" defense and its exotic pressure packages. The Ryans are also known for their tough, in-your-face style.
He brought that persona and attitude to the Ravens. In 2000, Lewis was the best player in the NFL. But the players who ran that team were a bunch of nasty guys named Sam Adams, Tony Siragusa, Michael McCrary and Rob Burnett.
Siragusa was arrogant and obnoxious. Adams had a split personality depending on the weather. McCrary was an overgrown kid who had as much energy playing on Sunday afternoons as he did in the parking lots with robotic toys. Burnett was the mean, quiet type who'd threaten any player that got out of line.
And guess who they were coached by? None other than Rex Ryan, also known as "Sexy Rexy," to some staff members at The Castle. Ryan's personality was as big as some of the players'.
"I think so," said Suggs when asked if there were some remnants of what Ryan left behind. "A lot of it is still around here. It's just the mentality. It's the mentality he taught. It's the mentality we have. It kind of went hand-in-hand when he was here. That's why he was so successful, we were so successful, and that's why we continue to be successful around here."
Even some of the current Ravens who never played for Ryan understand his stature with the team.
"I heard about him that he is aggressive, defensive minded, an old-school coach and a player's coach," said cornerback Jimmy Smith, drafted by the Ravens in 2011. "I know he coached here for some time and developed the Ravens mentality, and I know I have that type of mentality."
So do the Bills. They have the same philosophy of wanting to stop the run first, and then bring the pressure in passing situations. They have a strong front three led by tackle Kyle Williams and two good cornerbacks in Stephon Gilmore and Ronald Darby.
On the other side, the Ravens will be young on the left side of the offensive line with rookie tackle Ronald Stanley and either rookie Alex Lewis or third-year player John Urschel at left guard.
Ryan is going to be dialing up some blitzes.
"I think Rex always likes to come after people," Ravens quarterback Joe Flacco said. "That's in his nature. First game of the season, I think he'll probably do that a little bit just to see if we're prepared for picking up some of the blitzes and things like that."
You can bet on it, especially now that his twin brother, Rob, is an assistant coach. After Rob had unimpressive stops in Oakland, Cleveland, Dallas and New Orleans, Rex hired him in June. He has also hired former Ravens safety Ed Reed as one of his defensive backs coaches.
The two additions might be a sign of desperation. There have been numerous reports speculating Ryan has to make the playoffs this season and improve on last year's 8-8 record after the Bills finished 9-7 under Doug Marrone in 2014.
Ryan has some things working in his favor, especially in the AFC East, where New England quarterback Tom Brady will be suspended for the first four games and Miami has a new head coach. Overall, Ryan has a 54-58 record with only two winning seasons.
He is signed through the 2019 season, and doesn't seem concerned about his future.
"Eh. I don't get into that," Ryan said of those reports. "I'm just going to have my team prepared and play our tails off. That's what I do. It's never about me. But you ask me? I don't believe that."