Police expected to make more arrests in the coming days.
The younger defendant appeared briefly in the Lower Hutt District Court before Judge Arthur Tompkins, where he was granted interim name suppression.
He was remanded without plea to a date in November, to appear in the High Court at Whanganui.
A woman in the public gallery called out "I love you" to the man, who blew her a kiss before being led back down to the cells.
Detective Senior Sergeant Philip Skoglund said earlier today police wanted to thank the Whanganui community for their "courage and fortitude in standing against gang violence".
"Police continue to seek assistance from the public in relation to the movements of five men who walked to Kevin's address on the morning of 21 August."
Twelve people were already facing several charges as a result of the homicide inquiry, including threatening to kill, unlawful possession of ammunition and participation in an organised crime group.
The names of those 12 men were suppressed last month but suppression is to be reconsidered on November 30 when they are due to reappear in court.
Ratana's funeral was held on August 27 and attracted an increased police presence in Whanganui, including the eye-in-the-sky Eagle helicopter, as gang numbers in the city swelled to more than 100.
As Ratana's tangi was under way, police carried out a hefty raid on several Black Power houses around the corner from Puriri St, making a number of arrests and seizing guns.
Two weeks later Detective Senior Sergeant Paul Baskett said the inquiry had made "significant progress" but issued a public plea for information.
"… we know that there are people who have information and have not yet spoken to us. We believe those people are likely to have critical evidence relating to Kevin's death," he said at the time.
