Seahawks have the NFL's best defense again: How the fall of the 'Legion of Boom' led to the 'Dark Side'

The Seahawks enter the Divisional Playoffs as the Super Bowl favorites looking to win their second championship in franchise history. The first one came thanks to a stunning 43-8 thrashing of Peyton Manning and the Broncos' record-setting offense in Super Bowl XLVIII.

If the Seahawks are going to repeat what they did a dozen years ago, it will be with the same formula: the occasional explosive pass with a punishing ground game backed by the NFL's top scoring defense. It worked for Russell Wilson (in his second season), Marshawn Lynch and the "Legion of Boom" and it could work with Sam Darnold, Jaxon Smith-Njigba and the "Dark Side," which is Seattle's new self-ordained defensive nickname. The moniker could be a Nirvana track, but the defensive players chose the name because of the Pacific Northwest's gloomy weather during the fall and winter months of the season. Its defense was indeed so suffocating it earned Seattle the NFL's top scoring defense crown for the first time since the "Legion of Boom" did it a decade ago. 

Nasty defense was Seattle's ticket to top seed and first-round bye in a do-or-die game vs. the 49ers just two weeks ago. Darnold was rarely asked to make a big throw downfield and the Seahawks ran for 180 yards while holding San Francisco to one its worst offensive performances in nine years with Kyle Shanahan. They meet again Saturday night -- the sun will have set on Lumen Field. 

To understand where this new defense can take them, you have to understand where it came from and how Seattle is looking to ride a new No. 1 group to a Super Bowl while evolving from the "Legion of Boom" glory days to the "Dark Side".

"Legion of Boom" fall paved way for the "Dark Side"

It's hard to talk about an elite defense in Seattle without waxing poetic about another Seahawks defense that used to give teams nightmares. The "Legion of Boom" went on one of the greatest defensive runs in NFL history over a decade ago. 

They became the first team to lead the NFL in scoring defense for four straight seasons since the Cleveland Browns in the 1950s. They were debated as one of the best championship defenses of all-time alongside the 1985 Bears, 2000 Ravens and 2002 Buccaneers for good reason. They pulled off one of the most incredible defensive feats in league history by holding the Broncos to eight points in the Super Bowl after Denver had scored an NFL-record 606 points during the regular season and Peyton Manning threw for 5,477 yards and 55 touchdowns. 

All three records still stand today, even with a 17th game. 

One memory from this defense lives on. Richard Sherman's interview with Erin Andrews after making a deflection that was intercepted by future Super Bowl MVP Malcolm Smith to win the 2013 NFC Championship vs. the 49ers is immortal and stamped the Legion of Boom as the the defining force of their generation of football. 

The "LOB" was a brand of big personalities, big hits (jumbo safety Kam Chancellor used to rock people) and playmaking (Earl Thomas' chase-down forced fumbles) that took over the NFL in a flash and it went away in the blink of an eye. Injuries, old age and contracts (they had to pay Russell Wilson) all caught up the league's most feared defense too fast. Sherman (torn Achilles), Thomas (broken leg) and Chancellor (neck) all suffered season-ending (or career ending in Chancellor's case) injuries that more or less ended their time in Seattle by 2018. 

It's a crime none of the trio played with the Seahawks into their thirties. Michael Bennett was also traded, Cliff Avril suffered a career-ending neck injury and poof, it was over.

Mike Macdonald hired to be McVay and Shanahan's kryptonite

The downfall of the LOB and the lessons learned led us to the next generation of defensive brilliance. 

After all, the Seahawks had one of the worst defenses in the NFL in the post-LOB days where Pete Carroll and Wilson won enough track meets to stay relevant but only managed one playoff win. A new wave of offensive gurus came into the division between Kyle Shanahan and Sean McVay around the same time Seattle's defense began fading in 2017. Motion, jet sweeps, misdirection and deception became common NFL vernacular as Shanahan, McVay and Matt LaFleur's teams combined to score 99 points while eliminating the Seahawks in three playoff runs in 2019, 2020 and 2022. 

That made things crystal clear. A reset was needed. The counter move was to make then 36-year old Mike Macdonald the youngest head coach in the NFL after he led the 2023 Ravens to the title of top scoring defense as coordinator. Macdonald has proved to be exactly what the Seahawks needed as a great leader and communicator to usher in another winning culture while figuring out how to stop the NFC's best offenses. 

Seahawks general manager John Schneider said it best when he introduced Macdonald in 2024. "This is the future right here, this is where it's going … I think you're going to learn in getting to know Mike that he's a special dude." 

He was right. Macdonald's reputation from Baltimore has followed him to Seattle. The 2023 Ravens became the first team in NFL history to lead the league in scoring defense, takeaways and sacks in the same season, which was Macdonald's last with the club. Fast forward just two years and he's already rebuilt the Seahawks from the No. 25 unit in 2023 to the top defense in 2025.

He's only the third coach since the 1970 NFL-AFL merger to be the defensive coordinator and head coach of a top scoring defense after pulling it off with the Ravens and Seahawks. The other two were Rex Ryan and Bill Belichick. 

Macdonald's own innovative thinking has already helped neutralize two of the best thinkers on the other side of the ball. The Rams and 49ers are averaging under 23 points per game in eight games vs. the Seahawks under Macdonald, and he might have to go through them again in each of the next two weeks to make the Super Bowl. What a litmus test that would be.

Schneider rebuilt the entire defense in four years

The Seahawks slowly pieced together the talent to fit Macdonald's scheme predicated on a dominant front four backed by a physical and versatile group of linebackers and defensive backs. 

Schneider built the unit through equal parts draft, free agency and trade. There's not a single defender in the group with an active tenure on the team longer than four years. It's been a complete rebuild that has this new core standing shoulder to shoulder with the LOB.

Seahawks defense then and now

The Seahawks have had an absurd hit rate in the draft in the last four years. 

• 2022: It started with a masterclass in 2022. Boye Mafe, Coby Bryant and Riq Woolen -- all key players in this defense. 
• 2023: Schneider hit the jackpot with All-Pro corner Devon Witherspoon in the first round in 2023. He's since become the third defensive back in the past 40 years to make a Pro Bowl in each of his first three years along with Charles Woodson and Patrick Peterson. Macdonald credits Witherspoon's development for freeing him up as a defensive play caller. 
• 2024: Seattle drafted defensive tackle Byron Murphy in the first round the following year and he's been a game-wrecker on the inside. 
• 2025: The final piece to bring the top defense together was 2025 first-round pick Nick Emmanwori, a swiss-army knife who has done everything from defending the run to blitzing and excelling in coverage.  

So the top defensive player Seattle took in each of the last four drafts was Mafe, Witherspoon, Murphy and Emmanwori. Holy crap. 

The Seahawks have also signed or traded for four players that got a Pro Bowl or All-Pro selection in the last few seasons

• 2023: Seattle signed former Giants safety Julian Love to an affordable three-year deal worth $33 million. He's one of many versatile, hard-hitting defensive backs on the team. Seattle traded a second and fifth-round pick for Leonard Williams, who has lined up (and dominated) everywhere on the front four
• 2024: The Seahawks got another steal when they traded Jerome Baker and a fourth-round pick for linebacker Ernest Jones IV, who was a second-team All-Pro selection this season. He became the first linebacker with 125+ tackles and at least five interceptions in a season since LaVonte David in 2013. Macdonald praised him during last week's presser, "to really man the middle of the defense, especially with how much split safety we play, that's a tall task, but he's nailed it."
• 2025: The final piece on the Seahawks dominant front four was Demarcus Lawrence, signed to a three-year deal after an injury-plagued final year in Dallas

They may not have a treasure trove of superstars or future Hall of Famers like the "Legion of Boom" just yet, but don't be surprised if a couple of them leave their mark and have a significant playoff moment on their way to a Super Bowl.

How quickly Seattle built its new elite defense

Fear the Seahawks' "Dark Side"

Now you know the names, but you might not have caught on with the name. This isn't the "Legion of Boom 2.0." This is a phoenix rising from the ashes of the "LOB" with a new identity. The old was one of the best secondaries in NFL history. The new is a ferocious front four with studs at all three levels. 

Leonard Williams explained the origin recently. 

"We always hear of Legion of Boom," he said. "We were starting to get to a point like. 'Hey, maybe we deserve our own name, you know?' I think guys started coming up with names and stuff like that and I think Dark Side kind of stuck with us."

But what does it mean?

"The Dark Side is our defense. DLaw (Demarcus Lawrence) said it good at one point, he wants to turn the offense's lights off. We've shut offenses down with no touchdowns, no points at times, I think that's what it feels like when the "Dark Side" is playing against you, it's hard to get the ball moving, it feels like cutting your lights off, it feels like you're playing against 12 people."

12 as 1

12 as 1 is one of Macdonald's core defensive principles that goes beyond just playing in front of the "12", as in Seattle's 12th Man, which the Seahawks will be doing on Saturday. 

"A lot of times we see the ball carrier on the ground and pause the film to see how many blue helmets are in the picture," Williams said. "A majority of the time it's nine players standing over the ball carrier ... over time that's overwhelming and intimidating to offenses. When the offensive guy is getting off the ground and seeing 10 Seahawks around him, after a while and getting hit by so many of us, getting swarmed by so many of us, it starts to feel like there's more than 11 of us on the field."

A rewatch of the Seahawks' 13-3 win vs. the 49ers in Week 18 underscored that assessment. The 49ers were seemingly immediately on their backs as soon as they caught the ball. The Seahawks had just three missed tackles and the 49ers managed their third-worst yards after catch average (2.6) in nine years under Shanahan. 

"All 11 guys make it feel like 12 to the football," Witherspoon said. "We play with relentless energy and swag." 

Seattle's defensive ranks this season

Front four

Personnel-wise, the foundation of this special group is the front four. 

"We wouldn't be here without how our defensive line has played," Macdonald said Monday. Everything starts with them.

The Seahawks allowed the fewest yards per rush in the NFL this year (3.7). They also got pressure at the sixth-highest pressure rate in the league while blitzing at the seventh-lowest rate in the NFL. It's a similar formula that won Philadelphia the Super Bowl last year. You can put these four on an island and they can stop the run and create enough pressure without blitzing to help the secondary. 

Williams explained it like this, "When we can play with two high safety and stop the run with just four down lineman, knowing at least two or three of us are getting double teams, that's mean we're not only stopping the double teams, we're beating the double teams, (Byron) Murphy is one of the best in the league that I've seen do it in my career."

Williams and Murphy bring so much pressure and throw enough weight around to start a Beastquake 2.0. They have the most pressures (108), quarterback hits (35) and sacks (14.0) among any 300-pound duo this season.

Versatility and controlled aggression

The front four sets the tone and the versatility on all three levels brings it all together. Williams (defensive end, defensive tackle), Witherspoon (outside corner, slot corner) and Emmanwori (slot corner, linebacker) almost all split their playing time 50/50 at two positions. 

Rookie playmaker Nick Emmanwori is a Kyle Hamilton clone. The numbers between Hamilton and Emmanwori on Macdonald's top-scoring defenses are almost identical. 

Hamilton wears a ton of hats in Baltimore from box safety, to slot corner and deep safety and Emmanwori has been a major disruptor on Seattle's defense in a similar way. He has the fifth-most snaps played in the box among DBs (364). 

He's the chess piece that marries together an elite run defense with blanket coverage. The Seahawks are the first team since the 2015 Super Bowl-champion Broncos to rank top two in both yards per rush and yards per pass attempt allowed.

It's an incredible feat, especially on the ground, considering since they play the least amount of base defense in the NFL and play among the most shell coverage.

"Some of the things you're going to ask Nick to do are a little different than what you'd ask a linebacker to do. But, in terms of how you manage your roster, he's basically playing the linebacker position," Macdonald said this week. "We've essentially turned into a base 43 team with a crazy athletic SAM (linebacker), is what we are."

The rookie was making highlights all over the field in Week 18 at San Francisco. 

His presence was not lost on 49ers offensive coordinator Klay Kubiak. 

"That's their personnel, that's what they want to do, and they have the people to do it, I mean you look No. 3 (Emmanwori), he's this nickel body for them, but he's so big and long, he has the ability to play the run at a very elite level, like a good linebacker," Kubiak said. "But he's also really athletic and he can cover. He's really a jack of all trades."

49ers quarterback Brock Purdy took note of Emmanwori's presence during his press conference this week. 

"He's a young, talented player that flies around, he's got length, he's gonna bring it for four quarters, he can cover, drop back in zone, he can do it all," Purdy said. 

The former South Carolina Gamecock is having a similar impact to Chiefs cornerback Trent McDuffie, one of Steve Spagnuolo's key pieces during back-to-back Super Bowl runs. The Seahawks play almost exclusive zone coverage (80%, third highest in NFL) and rarely send extra pressure but when they do Macdonald comes from the Rex Ryan school of exotic blitzes. The Seahawks sent a defensive back pass rusher the fifth-most times in the NFL this year (109) and Emmanwori led all defensive backs in pressures (18).  

When you can stop the run without a dominant front four and nickel or dime defense behind it, all without blitzing, all with two-high coverage, it's an incredible luxury in the passing game. No defense faces shorter passes on average than Seattle this year. They keep everything in front of them and didn't even allow a play to gain more than 14 yards through three quarters in their last game. 

Between the front four, gifted linebackers, Emmanwori playing hybrid linebacker/slot corner and a physical secondary, it's no wonder why they call this unit the "Dark Side". 

Shanahan vs. Macdonald on Saturday

None of it matters, though, unless this defense repeats what it did vs. the 49ers in Week 18. They took the middle of the field away from Purdy, where he does most of his damange, and held from San Francisco to three points, its fewest in a game since the first contest of the Shanahan era. You can understand why he was heaping praise on them when he addressed the media this week.

"They are extremely talented at all three levels," Shanahan said. "They have a very good scheme. It's very balanced and they can hit you in any way ... the personnel is perfect for their scheme." 

None of Shanahan's misdirection or creativity could phase Macdonald & Co., who didn't play a single snap in base defense, not even against the 49ers patented 21 personnel when they roll with two running backs (Christian McCaffrey, Kyle Juszczyk) to create mismatches all over the field. Macdonald beat Shanahan at his own game. 

The 49ers couldn't run at all with base offense vs. the Seahawks' nickel and dime defenses -- again a testament to the Seahawks' front four and the hybrid Emmanwori. That's been the case all year as Seattle has allowed a microscopic 3.4 yards per rush against base offense without base defense. Their smalls are better than your bigs, simple as that. 

The silver lining for San Francisco is the reinforcements coming. Left tackle Trent Williams didn't play in Week 18 which showed as the 49ers got zero push on the ground and Purdy was pressured on almost half of his drop-backs. The last play of the game where Purdy nearly got killed after Williams' backup was beat sums it up best. 

The 49ers won't have tight end George Kittle but there's optimism they'll have wide receiver Ricky Pearsall back after he's missed the past two games, including the Week 18 loss. Pearsall had 108 receiving yards in Week 1 in Seattle and can help space the field. He would be a huge addition after Purdy averaged the second-shortest average pass length of his career (4.8 air yards) in Week 18. 

It will be tough to get the best of Kyle Shanahan in back-to-back games. But if anyone can do it, it's Macdonald. It's also tough to trust Sam Darnold enough to endorse Seattle as a Super Bowl favorite. If anything can erase and smother those concerns, it's clearly the "Dark Side."