John D. Sutter is a columnist for CNN Opinion who focuses on climate change and social justice. Follow him on Snapchat , Facebook and email . The opinions expressed in this commentary are his. Warning: This column contains language some may find offensive.

Orlando, Florida (CNN) He's 6-foot-9 and built like a redwood. Everyone calls him "Tree." On Tuesday afternoon, as storm clouds prepared to gather over this embattled city, Tree walked into a tattoo parlor and scribbled eight names on a sheet of paper.

Amanda, Mercedez, Deonka, Peter.

Stanley, Angel, Enrique, Shane.

He almost can't say them aloud.

The eight are only the very closest friends that Eric "Tree" Rountree lost this week after a shooter opened fire on Pulse, a gay nightclub here in Orlando, killing 49.

Tree knew 17 in all.

But he'd known these eight the longest. He met them during the six years he spent as a security guard at another gay bar in town. The eight and others welcomed Tree, who is straight, into their family. They loaned him a car for nine months when his broke down, gave him a place to crash when he needed it, fronted him money to help with the bills.

Eric "Tree" Rountree, 31, at an Orlando tattoo parlor this week.

They taught him their history, too.

"Since I can remember, we've only had each other," said Giovanni Nieves , a hairstylist and friend of Tree's who lost five friends of his own in the massacre. "We're the only ones we cling to because we face so much rejection from all the other communities surrounding us."

He heard their stories of being harassed, understood the LGBT community had seen too many of its young people thrown out on the street by ignorant parents, seen too many of its brothers and sisters committing suicide because people called them faggot or sissy.

This was a group -- the eight, and so many more -- who accepted Tree for exactly who he was when others hadn't. They saw past the ink and the nose ring and the size 19 shoes. They didn't tease him about his weight or his height -- didn't make him feel like a freak or an ogre. They didn't care when he told them that he stole cars at age 13 for money. They understood this gentle giant had changed.

They'd been judged unfairly, too.

All this helps explain why this tragedy is felt with such piercing depth in parts of Orlando.

Pulse was more than a bar. It was a family and support network.

It had to be.

"Latin night (at Pulse) was like church to us," Nieves told me.

Within segments of the LGBT community and its allies here, the question sadly isn't, "Did you know someone." Instead, it's "How many someones did you know?"

Two. Ten. Seventeen.

As I kept asking the question this week, the numbers only grew larger.

'I can take a lot of pain'

Tree is 31, and he started working security at bars at age 16.

At first, he just wanted to drink, and he figured it would be hard to use another person's ID when your name is Tree and you're NBA-tall. He soon realized, however, that protecting people was his calling. It's a role that seemed obvious. He'd always been big. He weighed 8 or 9 pounds at birth, he told me, and by age 5 or 6 he was nearly 5 feet tall. So he became the big-little brother, first using his stature to defend his older sister, then turning it into a profession.

He worked private security, a job that would see him stabbed twice, he told me, once in the side and once in the butt cheek. "I can take a lot of pain at once," he said.

Rountree knew 17 people killed in the Orlando mass shooting.

Then he started working security at Revolution, a now-closed gay bar in Orlando. Right away, he knew that he was needed. There weren't the vicious brawls he'd encountered at straight nightclub jobs. But there was always the chance of a looming threat, the people who hated this community's love. Tree knew his presence made people feel safer.

And he liked being the feel-safe guy.

Perhaps it's no surprise, then, that the news of the gay club massacre -- the deadliest mass shooting in American history, the largest terror attack on U.S. soil since 9/11 -- left Tree not only with a staggering personal void but also with a nagging sense of guilt. He knows that's misplaced. He didn't work at Pulse, never had. But he was the protector. He'd trained for the worst. Knew how to respond. What if he had been there the night of the shooting?

Could he have saved that friend whose smile lit up any room?

Could he have saved the eight, the 17, the 49?

Probably not. He knows that.

But he wishes he'd had the chance.

'Everyone get out'

News that the eight had died came in spurts, an IV-drip of misery flowing from Facebook, text messages and phone calls. "Everyone get out of pulse and keep running," the nightclub wrote on its Facebook page at 2:09 a.m. Sunday. In four hours, dozens would die. A marriage plan would be replaced with funeral arrangements for a young gay couple. A son would lose his mother , and a mother would lose her son . Amanda Alvear, inside the club, posted a video of the shooting on Snapchat. In it, you hear dance tracks, then gunshots, then silence.

"Two more wonderful women I had the pleasure of knowing are now gone," Tree wrote on Facebook at 4:16 a.m. Monday. "Mercedez and Amanda were two wonderful people."

Two of his eight.

I met Tree on Monday afternoon at a memorial for the victims outside the Dr. Phillips Center for the Performing Arts in Orlando. He brought two flowers with him, one blue, one red; one for friendship and another for love, not that he knows how to separate the two anymore.

He'd driven back from a family reunion in Kentucky to be there.

Rountree worked for six years as a bouncer at a gay bar.

He couldn't stay away.

The other family needed him.

He arrived on Sunday and knew he had to help, had to do something. He tried to donate blood but the sign-up sheet was full. So he picked up a bunch of ice and snacks and started delivering them around town. He figured people would need ice on a blistering Florida day.

He wasn't sleeping, trying to stay busy.

Later Monday night, Tree went to a public vigil for the victims even though he wasn't sure he could do it. He stood in a crowd of thousands holding candles, thinking not about himself and the 17 friends he lost but about other people in this adopted community and how much deeper their pain must be. What about the mothers and fathers, husbands and wives, brothers and sisters? The number of people a person loses doesn't tell the whole story, doesn't elicit the depth of the anguish. Still, Tree is certain others lost more friends than he did. His girlfriend, Elizabeth Velez, 24, told me Tree spent much of the service hugging other people and asking if they needed help. What about you? she thought. Don't you need help, too?

"I don't know how to comfort someone who deals with knowing that 17 people are no longer here in this world, and in their lives, at the drop of a dime," Velez said.

"You would never wish that on your worst enemy."

Photos: Orlando vigil for shooting victims Photos: Orlando vigil for shooting victims People light candles during a vigil one day after a gunman killed 49 people at a gay nightclub, marking the deadliest mass shooting in U.S. history Hide Caption 1 of 7 Photos: Orlando vigil for shooting victims Attendees make signs with messages like "#OrlandoStrong" and "We Stand Together." Hide Caption 2 of 7 Photos: Orlando vigil for shooting victims Mourners embrace at the vigil, which took place in front of the Dr. Phillips Center for the Performing Arts in downtown Orlando. Hide Caption 3 of 7 Photos: Orlando vigil for shooting victims Family and friends of shooting victims Leroy Valentin Fernandez and Xavier Emmanuel Serrano Rosado attend the vigil. They were wearing matching "RIP Eman & Roy" shirts. Learn more about the victims Hide Caption 4 of 7 Photos: Orlando vigil for shooting victims A flower is placed on a long sheet of paper adorned with heartfelt messages. Hide Caption 5 of 7 Photos: Orlando vigil for shooting victims Thousands of people attended Monday night's vigil in Orlando. Hide Caption 6 of 7 Photos: Orlando vigil for shooting victims The crowd holds up candles during a moment of silence for the victims. Hide Caption 7 of 7

At the vigil, the names were read over a loudspeaker.

Then a church bell tolled 49 times.

One for each of the fallen.

Tree got emotional and had to walk away from the crowd.

Like a shovel dumping dirt on the grave, he told me.

The eight were really gone.

'Am I bleeding?'

Tree talks about the friends he's lost as a collective -- the eight, the 17 -- because remembering them one by one, toll by toll, is still too intense. In an interview, he wasn't able to say the 17 names aloud. Please don't ask me to do that, he asked me gently.

I just can't go there right now.

The day after the vigil, as soon as he got out of class (he's studying to be a radiologist), Tree drove to Ink Spot Tattoos and wrote down eight names on that piece of paper.

Tree is a towering person covered in tattoos, and he's quick to tell you the ink is for him, not you. So maybe that's why he turned the names of the eight into a personal code.

AA, MF, DH, PO.

SA, AH, ER, ST.

Eight sets of initials.

The Orlando massacre is inked into Rountree's arm.

In the tattoo, the letters encircle a symbol that includes a heart and an EKG line.

Like their blood was coursing through him.

One pulse.

It was still sunny outside, but thunderclouds would darken the sky in a matter of hours.

Storms so intense they knocked out power in parts of the city.

Inside, I listened to the rattle of the tattoo needle.

Tragedy etched into forearm.

"Am I bleeding?" Tree asked, not aware of the symbolism.

No, the artist said.

"Your skin is way too thick for that."

It's sometimes hard to see what's just beneath the surface.