Emily Johnson sneaked up behind her 3-year-old great-nephew and dipped his face into a cake, knelt down next to him, and smooshed her nose into his, covering them both in icing as the little boy howled.

It was a small moment Thursday afternoon in the middle of a West Philadelphia street party when Johnson willed herself to smile. She was trying to be strong for the kids, pressing through the raw pain of what happened just hours before: She’d laid eight red roses on a casket that held 16-year-old K.J., her beloved only child, who was fatally shot.

They were inseparable. So at that post-funeral get-together, each time a smile stretched to her cheekbones, it radiated through dozens of people who’d gathered, determined to honor Kaylin Jahad Johnson the best way they knew how: mimicking his electric smile and finding a little joy, even in the depths of despair.

“From day one it’s been me and K.J., us against the world,” Emily Johnson, 37, said. “I’m obsessed with him.”

K.J. Johnson’s loved ones, even as they struggle to make sense of the July 21 shooting, are telling his story to anyone who will listen. They want the neighborhood, the city, and the world to know he was athletic, outgoing, ambitious, and kind — to know exactly who is lost by gun violence’s toll, and the sprawling grief that just one shooting can generate.

Because they know the reality: Shootings are often defined by numbers. The number of people hurt. The number of gunmen, of witnesses, of bullets fired. The number of people killed in Philadelphia so far this year, a figure that has climbed to 319, on pace to reach an unprecedented height by year’s end.

But behind that number are thousands of people trying desperately to resist it, fighting for their loved ones to be remembered by a number that can’t really be counted: the number of people whose lives were touched.

“K.J. is not a number. He never was,” his aunt, Shawneir Collier, said. “Everybody who he came across he made an impact on. That’s why we celebrated the way we did.”

Among those affected are those who knew Tommie Frazier III, 18, Johnson’s childhood friend. The two were killed when gunmen shot into their car in broad daylight near 56th and Vine Streets. Another friend was wounded. They were on their way to play basketball. No one has been arrested.

Emily and K.J. Johnson spoke on the phone eight minutes before shots rang out. The last thing he said to her was: “Love you. Bye, Mom.”

Frazier’s mother, Umbrenda Barksdale, said ensuring her son is not a statistic means pressing to bring his killers to justice so that another mother “never has to feel this pain.”

She wants her son remembered as who he was, the type of kid who was a little shy at first, then opened up once he got to know a person. Protective of his mom, he always checked in with her before he went to bed.

Frazier was enrolled at Simon Gratz, where 1,100 high school students are now touched by the shooting’s tentacles. There are 500 students at Boys’ Latin High School, where Johnson attended, who will return later this summer without their boisterous classmate.

There are coaches and mentors and teachers who became family. There are the regulars at Christy Recreation Center, where Johnson and Frazier will no longer be mainstays. There are the football and basketball teams, and the teenagers who grew up in West Philly, along with their mothers who saw K.J. as one of their own.

“They killed two people, but the ripple effect is devastating,” said Jonathan Hall, who owns a music studio in West Philadelphia and mentors young men. “It’s like a puzzle. You take away one piece, and you’re left with not a full picture.”

The missing piece was clear in the dozens of people who attended vigils for Johnson and Frazier in the days after the killing, and in those who gathered around the Overbrook Monarchs’ football field Saturday in remembrance of Johnson. They erupted in cheers when Sonantonious Moore, the executive director of the youth sports league, retired the jersey number “0,” which K.J. had insisted on wearing in his days playing football.

The missing piece is clear in Kaiya Newell, the 17-year-old cousin born two months and four days before K.J., whom he called his twin. She said the thing she’ll remember most is that he said “I love you” to everyone he met.

It was clear when hundreds of people crammed into the Christ Community Church on Thursday for Johnson’s funeral, and when his 14-year-old cousin, Stanley Newell, wearing the same red sweatsuit Johnson was buried in, draped his body over his best friend’s casket, overwhelmed with grief.

And it was perhaps most clear when that full sanctuary roared in applause, delivering a standing ovation for Emily Johnson after Boys’ Latin assistant principal Robert Parker told the room: “She did a phenomenal job.”

Johnson’s obituary was read aloud by Asia Thornton, a 28-year-old friend who feels like family. She read it in the present tense, saying his story is far from over.

“He is present,” she said. “And he might be the kid that helps change Philly.”

And then, Parker spoke directly to the young men, telling them that those who love K.J. know “he was trying to bring peace and hope.” The best way to honor him, he said, is to interrupt the cycle of violence by understanding what it takes from the world — and what it took from a mother.

A preacher asked everyone to stand, hug the person next to them, and say what K.J. would have: “I love you.” And they did.

Photojournalist Jessica Griffin contributed to this article.