Online, Influencer Killadamente Inspired Millions. At Home, She Was a Single Mother of 2.

As a Dominican American girl growing up in a small, immigrant neighborhood in Newark, Carol Acosta was relentlessly taunted about her weight. Her home life was chaotic, too: Neighbors said they heard shouting matches from inside her family’s small apartment.

But online, Ms. Acosta found an outlet for her struggles, using her humor and natural self-confidence to broadcast anti-bullying messages to young women. And in time, she rose to fame, known to her millions of followers by her online persona: “Killadamente.”

Ms. Acosta died on Jan. 3, according to her sisters, Katherine and Katyan Acosta, who said the cause was unclear. Videos posted to a TikTok account that appeared to belong to Katyan Acosta suggested that her sister had suffered a medical emergency and been taken to a hospital.

Ms. Acosta left behind two young children. She was 27.

Ms. Acosta’s celebrity among the Dominican diaspora and beyond, boosted by her music, fashion sense and messages of self-love and body positivity, was scarcely evident from her modest life in and around Newark, where she raised two children as a single mother.

Rafaela Chaves moved two and a half years ago into the apartment where Ms. Acosta had raised her two daughters in Kearny, N.J., just north of Newark. She said she could still remember Ms. Acosta as she was moving out: packing boxes in her pajamas and apologizing to Ms. Chaves for the mess as a toddler ran around.

Ms. Chaves said she didn’t realize Ms. Acosta was famous until six months after she moved in.

“I had a couple of pieces of mail that I received for her and gave to the landlord,” Ms. Chaves, 43, said, “and then he told me she’s a famous lady on Instagram.”

Ms. Chaves said she still received letters and exclusive offers from fashion houses hoping to connect with Ms. Acosta’s 6.7 million Instagram followers.

Some who knew Ms. Acosta before she became Killadamente said that the success she found as an adult stood in stark contrast to her childhood. Evelyn Calle, a middle school friend, said that Ms. Acosta was constantly bullied about her body size. Still, it never seemed to bother her, she recalled, noting that Ms. Acosta always stayed positive.

Ms. Calle, 25, said Ms. Acosta was sure she would one day become an online influencer.

Years later, Ms. Calle said, she realized that Ms. Acosta had become famous, just as her friend predicted, when she saw a viral video that Ms. Acosta had posted on Instagram.

“She reached her goals,” Ms. Calle said. “I’m so happy for her, so proud of her.”

Ms. Acosta wore many hats online. At times she presented herself as an activist, speaking out against domestic violence. At other times she flaunted glamorous outfits from the retail brand Fashion Nova through her partnership with the company. She promoted weight-loss medications, talked about motherhood and encouraged people to take care of their mental health.

She also dabbled in music, recording freestyle raps from her car or an apartment. The title of her 2017 song was Killadamente’s motto: “Me Amo y No Me Importa,” which means, “I love myself and I don’t care.”

Denise Mercedes, a Dominican American model, said content creators like Ms. Acosta had made it possible to have public figures of different shapes and sizes who could teach people, especially within the online Latino community, to love themselves regardless of societal beauty standards.

Ms. Acosta emphasized that self-love was about making decisions for your happiness, Ms. Mercedes said. It was that idea, along with Ms. Acosta’s use of Spanglish, she said, that resonated with her many fans.

Ms. Acosta was different from other high-profile influencers, said Isra Ali, a media studies professor at New York University. Unlike models like Nara Smith, who project a pristine domestic image online, Ms. Acosta’s content suggested a more modest lifestyle, one that an average person could understand, Ms. Ali said.

“It is a way of saying that they’re not going to acquiesce to a desire to be assimilated,” she said of Ms. Acosta. “They are going to assert identity, and they are going to use Spanish as a way of doing that.”

Ms. Ali said that such an online persona might not resonate with all Americans, but that it did with the Dominican diaspora — a community where people like Ms. Acosta could find their niche and attain significant influence.

In the days after her death, Ms. Acosta’s family, friends and followers flooded social media with posts wishing her rest and peace.

Katherine Acosta honored her sister with a string of memorable posts.

“How can I be like this with this great pain, sister, how can I know that you are no longer here,” one post read, adding: “You will always live in my heart like a light and I will never forget you.”