Michel Veillette, 34, was charged with four counts of aggravated murder, one count of murder and one count of aggravated arson in the Friday night fire, Officer Troy Nelson said.
Veillette also had been stabbed and remained in stable but serious condition Saturday at University Hospital in Cincinnati, Nelson said. He wouldn't speculate on how Veillette was injured.
Nadya Ferrari-Veillette, 33, was killed along with her children, Marguerite, 8, Vincent, 4, and 3-year-old twins Jacob and Mia, Nelson said.
Authorities said they received a call reporting the house fire just before 10 p.m. Friday. Investigators were trying to determine the cause of the fire.
Ferrari-Veillette, who had knife wounds and fire-related injuries, and one child were found dead inside the two-story house.
Three of the couple's other children were pulled from the fire from upstairs bedrooms and died at a hospital. None of the children had been stabbed, Nelson said.
Veillette had jumped out of a second-story window and was found on the ground.
Mason police Sgt. Jeff Burson said Veillette is unconscious and hasn't made any statements or hired a lawyer.
Autopsies were not completed Saturday, Nelson said.
Neighbors told The Cincinnati Enquirer that the family moved to the upscale neighborhood in Mason, about 20 miles northeast of Cincinnati, about 18 months ago.
Veillette traveled frequently for his job designing auto engines and was home only a few days a month, neighbors said.
