Von Miller went to hell and back this summer, and he recently returned to Colorado to tell his teammates — and the thousands watching Broncos training camp — tales of his journey.

Ty Sambrailo got an earful, as Miller blew past him repeatedly without contact in individual drills. Fellow offensive tackle Menelik Watson heard one story early in practice Thursday — a lethal spin move — and was so dumbfounded, he begged to hear another until it fully registered. Rookie offensive tackle Garett Bolles learned a bit, too, but the kid has been in the know since April, really.

Throughout the last seven months, Miller has shared snippets from his trip, often with camera filters, a steady beat of rap music and his friend and supporting actor, Cyrus Gray, at his side in professionally produced Instagram videos. For a stint in the middle of his odyssey, when he returned to Denver for organized team activities (OTAs), Miller recruited some of his teammates to tag along so they, too, could experience life in hell.

But hell hath no fury like a trainer disguised in a hoodie, black sunglasses and enough deceptive charm to call his clients “Sir.”

“That dude’s crazy,” said safety Will Parks.

That dude is better known as “Hell’s Trainer” and less known as Frank Matrisciano, a name few can match with a face because of his desire to stay out of the spotlight. He has no Twitter account. No Instagram documenting his famous clientele (his face is blurred out in Miller’s videos). No website and no interest in advertising his services.

Last week, Miller did enough of that for him, arriving at camp with quadriceps the size of watermelons, an explosiveness that has left onlookers chuckling in disbelief and a bend that defies the laws of gravity.

“I want to push my body to a spot that it has never been before,” Miller said in May. “You’re never guaranteed that working hard off the field will translate to on-the-field success, but that is what I am hoping for this year. I’ve never worked as hard as I am working this offseason.”

Attention at Broncos camp was supposed to be centered on the quarterbacks vying for a starting job. But Miller has claimed the spotlight, and this is no continuation of his Super Bowl 50 media tour.

Von Miller is on a mission.

“Controlled chaos”

Miller’s primary hell was stationed in San Francisco, with the blue sky and Pacific waters as backdrops. Four days after Denver’s 2016 season ended with a playoff-less thud, Miller jetted to northern California to meet with the man he had long heard about.

Miller’s agent, Joby Branion, had tried to convince Miller to get with “Frank” for years. Go to Frank, he would say. You need to go to Frank.

“Guys don’t really do this right away,” Matrisciano said. “They don’t really just jump into this training. For every 10 guys, only three stay.”

When Miller fell one vote short of being the NFL defensive player of the year, fell two and a half sacks short of the league lead and his Broncos fell one victory short of a postseason berth, he listened.

Miller rented a house in San Francisco, and every day that he could for about eight weeks, he and Gray — and others such as Shane Ray, who rotated through — endured Matrisciano’s “Chameleon Training,” a grueling regimen that emphasizes adaptation to unstable environments.

“I got tired of this cookie-cutter stuff,” Matrisciano said of his workouts. “You always want to do something different to shock the muscles. In San Francisco, the sand is unstable. That’s going to make someone stronger than it would if they were on a stable environment, like a football field. With me, I don’t like to put guys on hard surfaces. I don’t like to put them in a position where they’re going to put wear and tear on their bodies.

“The stuff is sort of crazy, but it’s controlled chaos. Everything I do is for a reason.”

Nature is Matrisciano’s playground, often literally.

Some days, Miller and Gray would sprint up the steep sandy hills at the base of the Golden Gate Bridge, wearing weight vests or carrying 50-pound medicine balls — sometimes both — until they reached a point of exhaustion.

Some days they’d toss a medicine ball against a concrete wall 50 times — then do it all again.

“I will not do things just to do them,” Matrisciano said. “I will not have someone train and pretend they’re getting stronger, or pretend their technique is good. If their technique is bad, we’ll stay right there until that technique is perfect. And then I’d move on with them.”

Some days they’d climb winding stairs up the cliffs, then work their way back down, drenched in sweat.

And some days, they’d crash a playground in an exercise of “Save the Kids,” in which they scale parallel bars as Matrisciano tells them that weight vests hanging off their shoulders — up to 40 pounds for Miller — are children needing rescue. The sand below their feet, he’d tell them, was a river. The slide to their right was a waterfall. The swings behind them were a massive fire.

Miller had to save as many children as he could, inching back and forth across the bars amid the pretend disasters. It was a mind game. They’re all mind games, with muscle and agility as byproducts.

“It’s reality,” Matrisciano said. “I’m not a fan of what people would actually consider lifting. That’s not reality. There is no bar, no pulley, nothing to aid you. So what they’re doing is actually lifting real weight.”

During OTAs, Miller flew Matrisciano to Colorado for Chameleon Training twice a week between team practices. Afterward, they returned to California for additional weeks of work before Miller reported to camp.

Miller’s altered physique — he weighs a little more than 250 pounds, with only 6.3 percent body fat — was hard to miss as he made his first precamp appearance in designer jeans that wrapped his thighs like Spandex.

“His body definitely changed and he looks ways better from last year as far as him being quick, being more efficient with his movements,” Parks said of the all-pro outside linebacker. “We kind of see it on film. As the DBs, we’re in the back so we get to see everyone up front, and he’s one of the guys who stands out as far as being fit, agile and moving at the same pace, if not faster, every rep. There’s definitely a difference.”

It was never more noticeable than on Day 2 of camp, as Miller bounced from individual drills against the offensive line, to team drills with a burst and energy unseen in past years.

“We all know who he is and what he’s capable of, so to have a guy like that to go against, you can’t ask for more,” Watson said. “He’s a perfectionist. And he’s also an alpha. Alphas don’t want to get beaten. When you go against a guy like that, and you’re an alpha, too, it only makes for good work.”

More snaps, more plays

In late June, at Stanford, Miller hosted his first summit for pass rushers — a gathering of the NFL’s leading edge rushers to share secrets and hone their craft. Miller said the summit was inspired in part by Peyton Manning’s annual passing camps at Duke with his brother, Eli, and their receivers.

Really, it was just a bigger, more formal version of the meet-ups Miller has had with rival players throughout his career, often in the offseason.

“At the end of the day, it’s going to make our game better,” he said. “It’s bigger than just my teammates and my Denver Broncos here. It’s a thing that can help improve the league.”

But when he was in the Bay Area or at Denver-area fields during this offseason, the focus was singular.

“If I can stay on the field, I can play eight snaps instead of five snaps,” said Miller, who has dealt with asthma since he was a kid. “It allows me more time to make plays and it allows me more opportunities and exposure to make plays. That’s been my whole goal this year. … I don’t want to be on the football field just going through the motions.”

Last season Miller played 930 snaps (81.2 percent of the defense), up from the 834 during the Broncos’ Super Bowl 50 run in 2015. Topping 1,000 snaps, as Denver cornerback Chris Harris does, may be ambitious. But perhaps not out of reach for Miller.

“I’m going to challenge him on that because I can’t come out. I’m like, ‘Hey, man, you need to stay in every play,’ ” Harris said. “I’m glad with the way he approached the offseason this year.”

Miller wants his and wants to help the Broncos get theirs. Instead of needing to come out and giving up another shot at the quarterback — another possible sack, another possible pressure, another opportunity to disrupt the opposing offense — he wants in on the action.

So far in camp, HE has been the action, and he’s made it look easy.

Maybe because he’s already been to hell and back.

“He was very serious and he earned it,” Matrisciano said. “You look at him now — believe me when I tell you this — next year when you see him, you’re going to go, ‘Damn, I thought last year was something.’ ”