The city the Saints call home is known for unexpected gifts. A piece of butterscotch hard candy with the purchase of a loaf of bread. A 13th donut. A set of beads tossed from a balcony.          

Lagniappe, it calls this tradition.

And now to this city comes a running back from the depths of the draft, ramming through a would-be tackler one minute, jumping over another the next, catching a pass and putting a move on a helpless linebacker, outrunning a group of defenders to the end zone, leaping high into the stands at the Superdome.

He is the front-runner for Offensive Rookie of the Year. He leads the NFL in yards per carry, with an average of 7.0. He leads the NFL in points scored by non-kickers, with 68. With four games left to play, he has become only the third rookie in NFL history—and the first in 37 years—to have 600 rushing and 600 receiving yards.

As he returns to play his hometown team in Atlanta on Thursday—with "404" tattooed on his chest—Kamara has the 9-3 Saints in prime position to unseat the Falcons as NFC South champs.

What an unexpected gift he has been.

In New Orleans, you can wander down a cobblestone alleyway and stumble on an incredible restaurant that hardly anybody knows about. That's kind of how the Saints found Kamara.

Kamara began his college career at Alabama but was buried on the depth chart beneath Derrick Henry and others. He didn't stay long before transferring to Hutchinson Community College and then Tennessee. There, Jalen Hurd was the man in the backfield. In the last two seasons, Hurd had 189 more carries than Kamara even though Hurd played four fewer games. Kamara was typecast as a third-down back.

"When you watch his film, he splits carries with a bigger back at Tennessee," Saints head coach Sean Payton says of his third-round pick. "So you don't get to see the vocabulary of runs you might see with other backs. You see him mostly in the offset gun, getting routes and draws."

What happened with Kamara is his ability to create mismatches in the passing game obscured his ability to run the football. He somehow was considered a "small back" at 215 pounds. He was rated a sixth-round pick by one NFL scout, who downgraded him for lacking patience and taking too many hits.

The truth is Kamara has a combination of burst, balance, power, speed, quickness and vision that have made him more dangerous than any of the four backs who were taken ahead of him.

"His reputation was this was a good guy coming out of the backfield catching passes," Saints quarterback Drew Brees says. "He is a much better pure runner than I ever expected."

Somehow, Kamara has been able to avoid tacklers (Pro Football Focus had his "elusiveness rating" as the highest in the league through Nov. 28, at 122.9, "a mark so high it would be the top elusive rating ever recorded in PFF history") while also running with an economy of motion (Next Gen Stats rates him as the most North-South runner in the league).

"He's one of the most slippery guys I've ever seen as far as his run game," says Adrian Peterson, who was Kamara's teammate for about six months before the Saints traded him to the Cardinals in part to give Kamara more opportunities. "He's not like me, where he's going to continue to pound and pound and pound you—but he has that ability in him. So with the combination, it just seemed effortless.

"He also has great patience and vision when it comes to running through the holes, but he's moving fast. It's hard to master that—speed and patience. To be able to do that as a rookie, it's spectacular. And I only see that improving. They got something special."

Thirteen running backs at the 2017 combine ran a better 40-yard dash than Kamara's 4.56, but Payton is certain Kamara plays faster than that time and many of those backs. On the field, the way you see him move looks so much like the player he created (dreadlocks and all) in his favorite video game, NHL 18, you'd be forgiven for thinking he's on skates.

Certainly, NFL defenders have been unable to catch him.

When he was 12, Kamara told his sister, Garmai Momolu, he was going to race her in her Chevy Malibu as an exercise to improve his speed. She dismissed him and pulled out of the driveway. Then she glanced in her rearview mirror and saw her kid brother, pumping his arms and gaining on her. She floored it, marking one of the only times anyone can remember when Kamara was left in someone's dust.

When Payton led a contingent of team personnel to Knoxville, Tennessee, to see Kamara in the spring, Kamara was under the impression they would just talk.

After the interviews, Kamara was getting ready to kick back and watch teammates run routes when Payton found him. "What are you doing?" Payton asked. "I came here to work you out. Get your cleats on."

Kamara didn't have his cleats. He ran to Tennessee's football equipment room and borrowed a pair. He says he didn't even have a chance to stretch before running routes.

"I was trying to tie my shoes while I was running out to the field," Kamara says. "OK, what do you want me to run?"

Kamara killed the workout. And between his amenability and his ability, he had Payton convinced then and there.

"I said then, 'I've got to have that player,'" Payton says. "And it has been a while since I felt that way about anyone."

Payton knew he would be the perfect player to fill the "Joker" position in his offense that once was played so well by Darren Sproles and Reggie Bush.

The Saints rated him as the 28th-best player in the draft, Payton says. But when they were on the board with the 42nd overall pick, the player they had rated 27th—safety Marcus Williams—was still available. They picked Williams, and Payton started to concede he wouldn't be able to get the player he had to have. He started thinking about the other running back the team had targeted, Tarik Cohen.

But it was worth making some phone calls. General manager Mickey Loomis recalls the Saints offered to deal with teams almost as soon as they had picked Williams. Finally, they found a partner in the 49ers, who accepted a 2018 second-round pick and a 2017 seventh-round pick for the 67th overall pick.

Since, Payton has come to admire Kamara as a young man as much as a running back. "Great kid, smart, good sense of humor, warm smile," he says.

That isn't to say Kamara is above the coach's wrath, though. In the second quarter against the Bucs on Nov. 5, Kamara scored a touchdown on a 33-yard reception and dropped the ball just over the goal line. It was a little too close to being ruled a fumble for Payton's liking. At halftime, just before the team left the locker room, Payton had a message for the rookie. "Go back to Tennessee with that!" he yelled. "Hold on to the ball! Don't you ever do that again!"

Kamara shrugged it off and scored another touchdown in the third quarter.

His teammates seem to be as fond of him as much as his coach is. "That's my guy, man," second-year receiver Michael Thomas says. "That's like my partner in crime. We're just happy to have a guy like that in this locker room and on the field with us on Sundays."

Kamara and Peterson also blended well. Peterson was open to mentoring him, and Kamara was open to being mentored. It was Peterson who gave him the nickname that teammates still use—AK41.

Running back Mark Ingram has ceded touches and attention to the rookie, and he could eventually have to move on because of him. But if he is resentful, he hides it well. He and Kamara share more than carries—they have weekly running back dinners and celebrate wins together.

"He's so humble," Ingram says. "He's a good guy, and I'm glad we have him here."

It helps that Kamara is not the type of back who needs to keep getting fed. "Whatever my role is, I'm going to play it," he says. "If it turned into you got to get 30 carries, I'm going to do it. But I feel you got to have two backs at least to be successful in this league. We have a good balance between me and Mark. It's been easy with me and him having the relationship we have and both being productive without any kind of friction between us."

Kamara also enjoys sharing with his new city.

After his last three touchdowns in the Mercedes-Benz Superdome, he has, incredibly, leapt over an eight-foot wall and into the stands. Kamara, whose 39 ½-inch vertical jump was the best of all running backs at the combine, calls it his "Fleur de Leap."

He's always been a pleaser.

When he was a child, he stood patiently while his sister used him and their brother Allen as mannequins so she could play fashion designer. She even dressed him in girls' clothes once before Mom raised her voice.

"One of the perks of being an older sister is they were like my little baby dolls, and I could play with them," says Momolu, who is 11 years older than Alvin and still talks to him every day.

Momolu tended to her brothers while their mother worked the third shift, often making a dinner of macaroni and cheese. To this day, it's Alvin's favorite meal. He's easy.

Kamara made a trip to a local Walmart the other day. While he was trying to pay for a phone case and a carton of Fairlife ultra-filtered milk, fans recognized him. Before long, many were asking for a photo, an autograph, a fist bump, a moment.

The cashier: "What are you doing here? Are you comfortable walking in here by yourself?"

Kamara: "Where am I supposed to get this stuff from?"

Kamara is just a regular guy. Except, of course, when he's wearing pads.

Kamara catches a screen pass from Brees in the second quarter against the Bucs. And then the play goes in slow motion. Before he makes his first move, he sees it all unfolding.

I can get around 54 with a move to the outside. Twenty-one is closing to try to pin me on the sidelines, but I can cut back inside, get away from him and then get back outside. Then I can run through 29. If Michael Thomas can get a piece of 98, I can make it to the corner of the end zone.

Back to real time, the play develops in a flash, exactly the way Kamara envisions it, and the running back intuitively scores another touchdown.

Being able to run through an NFL defense is a special gift. Being able to visualize the chaos before it ensues is a more special gift.

Kamara compares it to the scene in the The Matrix in which Keanu Reeves dodges bullets in slow motion.

"Things slow down for me," Kamara says with a shrug. "I don't know if everybody thinks like that. It's not like I blank out. I remember doing it after the play."

The gift traces all the way back to his early days of football. He started playing in elementary school and immediately decided it was his sport. By high school, the game was already slowing down for him.

"But it wasn't as detailed as it is now," he says. "I've always had this ability to stay one or two steps ahead in my mind. But it's developed more. The higher I keep climbing, the more detailed it's become."

Brees has noticed Kamara has unusual awareness and instinct. He says he knows where spaces are and how much time he has to get through them.

During the draft process, the Saints identified two important qualities in Kamara: intelligence (his Wonderlic score of 24 was highest of all running backs at the combine) and the ability to process quickly.

"So not only does he understand what he is supposed to do, but he can problem-solve on the field," Loomis says.

Payton expected Kamara to learn not only the "Joker" package, but everything else a Saints running back needs to know. Brees can't recall a rookie ever picking up things as quickly as Kamara did.

"We are very complex with what we do offensively, especially with formations, personnel groups and concepts," Brees says. "It's never felt too big for him, ever. You tell him something one time, and he's got it."

The primary concern with rookie running backs is blitz pickup. The next time Kamara makes a mistake on that assignment, it will be his first, according to Payton. For that, he hasn't blown an assignment in any situation this season.

When a young Payton was in charge of running backs at San Diego State in the early '90s, he coached Marshall Faulk.

"Most of the players in the room needed algebra," Payton says. "Marshall was ready for pre-calc. He knew everything. Now Alvin is the same way."

So much so, Payton says, that "he gets bored a little bit at practice."

Sometimes, it even feels like slow motion.

In a mugshot that was widely distributed during Kamara's college days, he looks sleepy and disinterested. "It leaves an impression," Payton says.

So does the diamond stud on the side of his nose and the bull ring through his septum. And the gold grill he wears on game days.

"People make a big deal about it because they are worried someone is going to rip out his nose ring," Momolu says. "But they have to catch him to rip it out."

He has heard about his appearance from opponents.

This guy has piercings. He can't run on us.

You look like a young thug.

If you really want to know who he is, look in his closet.

Though he may not be a workhorse, he is a clothes horse. "I'm into fashion," he says. "That's my vice."

Kamara has discovered and patronized some trendy boutiques that are walking distance from his downtown New Orleans pad. The Saints' schedule has enabled him to shop in London at Harrods and in Los Angeles at Barneys and Round Two.

He is especially into Balenciaga: hats, jackets, shirts, slip-ons and speed knits. He really likes shoes. He has a pair of Adidas Originals by Alexander Wang. One of his favorite pairs, by Rick Owens, goes for more than $2,000. He's worn them just twice.

In New Orleans, he has nearly 40 pairs of shoes. Then he has another entire closetful back home in Atlanta. And he still has a bunch at his old place in Knoxville.

"He has a really good shoe collection ..." says Momolu, who now works in fashion public relations and marketing. "Very cool, very understated. It stands out without trying to do too much."

The collection, Momolu points out, is "reflective" of its owner.

Payton realized there was more than you see on the surface with Kamara early on in practice, watching him make startling plays one after the other. The coach had needed to have this player, but he hadn't expected just what a treat he was in for.

"It's like, 'Whoa, wow,'" he says. "'This guy's something now. He's something else.'"

He pauses as he comes to another thought.

"This," Payton says, "is lagniappe."

Dan Pompei covers the NFL for Bleacher Report. Follow him on Twitter: @danpompei.