Michael Schumacher, 34, his wife, Kelly Layne Lau, 30, and the teen's one-time guardian, Caren Ramirez, 43, face torture, kidnapping and child abuse charges.
Ramirez was arraigned Monday in San Joaquin County Superior Court in Stockton, keeping her head down for most of the hearing.
All three have yet to enter pleas and are due back in court Jan. 5.
Each is being held in lieu of more than $2.2 million bail at the San Joaquin County jail.
Detective Nate Cogburn described in a sworn affidavit details of the alleged abuse that emerged during an interview with the boy.
The teen told investigators he had been seriously burned on his left arm when someone purposely lit a fire in the fireplace while he was chained there and sleeping. Authorities who later searched the home where the boy allegedly was held reported finding a blanket inside the fireplace, Cogburn said.
According to the affidavit, the three defendants had held the boy captive since mid-2007, beating him frequently, denying him food for days at a time and keeping him chained to the fireplace or a heavy table. The boy also recounted being choked with a belt until he lost consciousness.
"Though currently 16 years old, he appeared much younger due to malnourishment, and his body was predominantly covered with soot, sores and scars," Cogburn said.
The boy said he was regularly hit on the head with a baseball bat and was once cut with a knife, according to the detective.
Cogburn said the boy had an injured ankle that seemed permanently indented from being chained.
The boy explained that the defendants also forced him to take unknown pills, drink alcoholic beverages and smoke marijuana to keep him lethargic, the detective said.
In court Monday, attorneys for the defendants requested that future affidavits be sealed from public view. Judge Cinda Fox did not rule on the request but extended an earlier gag order prohibiting both sides from discussing the case.
