Despite receiving medical treatment, he died.
Soon after, a homicide investigation dubbed Operation Polar was launched and a house on South Rd in Blagdon and the vehicle used to transport Marshall to hospital became a focus for police.
In court, the accused made brief and separate appearances via audio-visual link from the New Plymouth Police Station.
Defence lawyer Kylie Pascoe asked for interim name suppression for the teen, as did lawyers Paul Keegan and Julian Hannam for the men.
Judge Gregory Hikaka granted the applications, which were not opposed by police.
The two men did not enter pleas and were remanded into prison custody by consent.
The youth was remanded into the care of Oranga Tamariki. He also did not enter a plea.
A High Court appearance of August 26 has been set down for the three.
A woman and a young man supported the youth and one of the men from the courtroom's public gallery.
Although arrests have been made, police said the investigation into the full circumstances of Marshall's death remains in the early stages.
Police are now appealing to the public for sightings and any information regarding two vehicles.
The first is a grey or silver 2005 Mazda Axela hatchback with a damaged front driver's side headlight. Police have requested sightings of this car in the Blagdon area of New Plymouth from August 2 until around 5.30pm on August 3.
The second vehicle is described as a smaller Japanese hatchback, possibly blue in colour and a 2010 model, seen in the vicinity of 100 South Rd on August 3 around 6pm.
Police have asked anyone with information about either vehicle to call its dedicated phone line on 0800 287 453.
The police inquiry into Marshall's death is the fifth such investigation for Taranaki in six months.
On July 31, the body of farmworker Jacob Mills Ramsay was found at a property in Upper Kina Rd at Oaonui, South Taranaki.
Two men, aged 39 and 18, have since appeared in court charged with his murder.
Other active homicide cases in the region include that of Leigh Beer, 31, who has been accused of murdering Emma Field, 21, on May 27; the unsolved May 7 death of Adrian Humphreys; and Henry Wensor who allegedly killed his wife, Levonne Wensor, on February 14.
