A hardworking mother who was devoted to her kids.

A young, supportive girlfriend who took three of her partner’s children in as her own.

An 11-year-old boy who loved basketball and making people laugh.

And an adorable 5-year-old girl with a big heart and a contagious smile.

Those are the four people who were found slain in an upstate basement apartment the day after Christmas — their bodies bound and their throats slit.

Police in Troy have called it the “worst” murder case they’ve ever investigated, and for friends and relatives of Shanta Myers, 36, her children Jeremiah, 11, and Shanise, 5, and her domestic partner, Brandi Mells, it’s been a nightmare.

“You have to understand how painful and unforgettable this is,” said Myers’ sister, Shakera Symes.

“It is going to devastate us for a very long time,” she told Spectrum News. “And to have to raise Isaiah, the oldest, knowing that he lost his entire family that day, that’s not a job that’s going to be easy for me.”

Isaiah, 15, is now all who remains of the Myers and Mells family.

“I just want to face the people that did this to my family,” Myers’ nephew, Khalif Coleman, told The Daily Gazette. “I just want to face them face to face and ask them why, just why?”

Myers was described by friends and family as a “great mother” who took her kids to school and picked them up every day, once worked at a homeless shelter, and had been toiling at a fast-food restaurant to support her kids.

“She was just a very sweet, sweet girl,” Equasia Watson, 30, who lived on the same floor of a River Street housing complex where Myers and her children previously resided, told The Post.

“I knew her from when she moved here from down South,” she said. “My son played with her son. We had dinners together. She took her kids to school. She went to work. She got her kids from school. She was always with them kids. She was a great mother.”

Myers’ sister told Spectrum News that Mells, who began dating Myers three years ago after the two met at a bar, loved Jeremiah and Shanise very much and treated them as her own.

The 22-year-old woman had been a student at West Genesee HS in Camillus and was originally from Newark.

“She was a little person, but her heart was bigger than she was,” close pal Dria Hector told NBC News, noting how Mells had dwarfism.

“She was very real. She spoke the truth. She was a sweet person, but she could have her bad days, like we all do.”

Symes said Isaiah had been living with the family for about two months and was at a basketball tournament in Massachusetts on Tuesday when the bodies were found.

Autopsies were conducted Wednesday, but officials haven’t provided information on preliminary results. Cops said Thursday that they still had no suspects.

Myers moved to Troy from North Carolina around 2011, according to friends. She worked at the local Joseph’s House homeless shelter and more recently at a Sonic fast-food eatery.

A local pastor said Myers and her children were much loved and respected in the neighborhood.

The Rev. Jackie Robinson of Oak Grove Baptist Church said that Myers had worked as a bus monitor and that her children were active in youth programs.

Shanise was a student at School 14, and Jeremiah went to Troy Middle School. The Troy schools chief on Thursday said the district would provide grief counseling.