Two nicknames define what will one day be remembered as the glory days of the Seattle Seahawks: Beast Mode and Legion of Boom.

The monickers themselves conjure up vivid images: Power. Intimidation. Quirkiness. Fun. Lombardi Trophy.

Last Wednesday, the Seahawks formally severed ties with Beast Mode when they traded Marshawn Lynch to the Raiders for a slightly better draft position next year. In reality, they've been struggling to replace Lynch's productivity — not to mention his aura — since his initial retirement after the 2015 season.

And now, with their actions in the NFL draft that ended Saturday, you can see the Seahawks preparing for life after Boom. It's not something that will likely manifest itself in 2017, but in the harsh reality of the NFL, you have to perpetually gird yourself for the ruthless turnover and inevitable diminution of career primes.

After going several years blissfully free of the need to spend valuable draft capital on the secondary, the Seahawks dived headlong into the DB pool. On Friday, they selected Central Florida cornerback Shaquill Griffin (No. 90 overall) and Michigan safety Delano Hill (No. 95) with consecutive third-round picks.

And bright and early Saturday, with the fourth pick of the fourth round, they grabbed Colorado safety Tedric Thompson (No. 187). That's on top of free-agent safety Bradley McDougald, signed earlier this offseason to a one-year, $1.8 million deal by Seattle with $750,000 guaranteed — and the selection of another defensive back, Cincinnati's Mike Tyson, in the sixth round Saturday. He was a safety in college but said the Seahawks told him he would compete at cornerback.

It smells vaguely like a changing of the guard ... or at least the first steps toward one. Not since the 2010 draft, when Seattle chose Earl Thomas in the first round and Walter Thurmond in the fourth, had the Seahawks used a pick in the fourth round or higher for a defensive back. There has been little need to do anything but dabble in a sixth rounder here (Eric Pinkins in 2014) or a seventh rounder there (Ryan Murphy in 2015).

John Schneider said Saturday this was merely the way the draft fell — it was laden with talented defensive backs, and "we followed our board," he said. "That's just the way the board came off. We didn't want to start just jumping players. That's when you get in trouble."

Yet with all these new defensive backs, the possibility for developing the successors to the magnificent no-longer-baby Boomers is enhanced, if not encouraged.

Thomas has been the heart and soul of the Legion of Boom, along with Kam Chancellor (fifth round in 2010) and Richard Sherman (fifth round in 2011). That's six years with that vaunted threesome. But time marches on, often at an accelerated rate in this profession. One of the founding Legion of Boomers, Brandon Browner, left after the 2013 season. And now you have to wonder how much longer the remaining trio will be together.

No one needs to be reminded of the ongoing Sherman drama. Though the completion of the draft without a Sherman trade is the most definitive signal yet that he will be back for the 2017 season, his long-term future with the organization remains very much in doubt. While he is signed through 2018, there clearly is a rift of some sort that has initiated a very public effort by Seattle to trade Sherman — perhaps at his behest.

Chancellor, meanwhile, is entering the final year of his contract, as is cornerback DeShawn Shead. Thomas is signed for two more years. It's an appropriate time to envision Legion of Boom, the Next Generation.

That's not to say this unit, if healthy, will not be formidable in 2017. Thomas, Sherman and Chancellor are all still impact players. But there have been definite signs of wear and tear since the Legion of Boom's peak in 2013, when the Seahawks' secondary turned in one of the most dominating seasons in NFL history. They allowed the fewest passing yards in the league (172), the fewest yards per catch (5.8), the lowest opponent's passer rating (63.4), and grabbed the most interceptions (28).

Fast forward to last year, when the Seahawks finished eighth in passing yards allowed (226), 18th in yards per catch (7.2), 9th in passer rating (85.0), and tied for 21st in interceptions (11, the lowest total of the Pete Carroll era). In their playoff loss to Atlanta, the Falcons drove 99 yards for a back-breaking touchdown at the end of the first half, nearly all of it through the air, en route to a 36-20 triumph.

The Seahawks played that game, as well as the final four regular-season games and their playoff win over Detroit, without Thomas, who had suffered a broken leg. They gave up 34 or more points in three of those six games and didn't have a single interception, which merely highlights Thomas's still-vital importance to this secondary. Chancellor missed four games last year with a groin injury. Shead tore his ACL in the Falcons loss and may miss the start of the 2017 season.

Coach Pete Carroll said he's eager to view his new crop of rookie defensive backs.

"It will be really fun to see how these guys fit in," he said. "They're all real competitive guys. They've all been great players in their programs. It's a real competitive room, and we would not take guys that would not be able to handle that. We think they're going to add to it. Also, our older guys have done a great job of mentoring, and we're going to count on that as well."

It's hard to imagine the Seahawks without their swaggering, staggering Legion of Boom. And we won't have to in 2017, it appears. But as this year's draft made crystal clear, it's time to start wrapping your brain around the possibility.