ALAMEDA -- Dennis Allen seemingly came out of nowhere.He blew past Todd Bowles. Overtook Marty Mornhinweg at the turn. And outlasted seeming clubhouse leader Winston Moss.Raider Nation, introducing the man known in coaching circles simply as "D.A.," the 18th head coach in Raiders history, teaming with new general manager Reggie McKenzie to usher in a new era in Silver and Blackdom.So how exactly did the 39-year-old defensive head-coach-in-waiting known only to a handful of football lifers become more than a blip on McKenzie's radar, and in such short fashion?"I never met him," a smiling McKenzie said after Monday's formal media conference. "Nobody really pushed him on me."You could say McKenzie was smitten with Allen from afar after seeing how improved Denver's defense was in 2011 under him, even if McKenzie's Green Bay Packers beat Allen's Broncos, 49-23, in Week 4. It was how the defense started to jell later in the season, even if Tim Tebow got the credit."Their defense was really keeping them in (the playoff race)," said McKenzie, who knew Denver coach John Fox was a defensive mind, but wanted to know who was actually running the Broncos defense as its coordinator."Then I saw Dennis Allen, so I started researching," McKenzie said. "That's how it started. My research led me to (say), 'Let me put him on this list to make sure I talk to him.' Like I said, the more I talked to the players who played for him, the coaches who coached with him, it was raving reviews."So McKenzie flew to Denver to interview Allen on Jan. 18. Then he secured a second interview in Mobile, Ala., during Senior Bowl Week last Tuesday night that Allen aced, sealing the deal."When (Reggie) called me that night, and it was late, he said, 'Mark, I found my guy,'" said Raiders owner Mark Davis. "And I knew then he had found the guy he was looking for."They struck a handshake deal and spent Wednesday hammering out the details. Some 48 hours later, the Raiders announced a media conference for Monday to introduce Allen."I heard a lot of people talk about what a great tradition that they had here with the Oakland Raiders," Allen said. "At the end of the day, what I was really concerned with was who are the people that are leading the organization now? The people who are leading the organization now are Mark Davis and Reggie McKenzie, and when I looked across the table at Reggie McKenzie, I knew that was a man that I believed in and that I trusted in."That was the only thing that was a concern to me, and that was what really drew me to this job."Allen, who turns 40 on Sept. 22, also interviewed for the St. Louis Rams' head coaching vacancy, which eventually went to Jeff Fisher.So how did that first phone call from McKenzie go down?"I really wasn't expecting it," Allen said. "Coach Fox told me that the Raiders had put in a request to speak with me. I was obviously really excited about it. There are only 32 of these jobs available, and anytime you get that opportunity, it's a wonderful opportunity. Especially with this organization. It's a great time to be with this organization. There's a rich history but the future is extremely bright."Almost as bright as the stars in McKenzie's eyes when he interviewed Allen, and got to know him better. Surely, it had to feel strange to feel such an instant connection, yes?"Strange, but it was exciting," McKenzie said. "I was glad that I had that feeling. That's what you go out to interview guys for. You want that connection. I wouldn't say strange but it was good."