A 14-year-old boy has been charged with the murders of Mason Rist and Max Dixon, police said.
The teenager, who cannot be named for legal reasons, is the fifth person charged with murdering the two boys.
He appeared at Bristol Youth Court and was remanded into custody to appear at Bristol Crown Court on Tuesday.
Earlier on Monday a 17-year-old boy was remanded into custody by Bristol Youth Court accused of murdering Mason, 15, and Max, 16.
He will also appear at Bristol Crown Court on Tuesday.
The boys were stabbed during an incident in Ilminster Avenue, Knowle West, Bristol, on the evening of Saturday January 27.
Local residents went to help the teenagers and police were on the scene within minutes to provide first aid.
They were taken by ambulance to Southmead Hospital and Bristol Royal Hospital for Children, where they died in the early hours of Sunday.
On Monday a hearing for two boys, aged 15 and 16, and 44-year-old Anthony Snook – who were all charged with murder last week – was held at Bristol Crown Court.
The three defendants were excused attendance but were represented in their absence by lawyers.
Judge Peter Blair KC, the Recorder of Bristol, fixed a plea and trial preparation hearing for April 26 and remanded them into custody.
Jamie Ogbourne, 26, of Bishport Avenue, and Bailey Westcott, 22, of Vowell Close, both Bristol, who are both accused of two charges of assisting an offender, will also appear in court again on April 26 after the judge moved their next hearing.
A provisional trial date of October 7 has been fixed.
Avon and Somerset Police said a 46-year-old man had been arrested on suspicion of assisting an offender and remains in custody for questioning.
A 14-year-old girl and a 49-year-old woman who were also arrested on suspicion of assisting an offender have both been released on conditional bail.
A total number of 13 people have now been arrested as part of the inquiry.
Two of the others who were arrested have been released on conditional bail and no further action has been taken against another arrested person.