Deadline reports Segarra's Vigilate will be an ally of Oliver Queen and a series regular.
The character in the series is described as: Adrian Chase, Star City’s new district attorney and an ally of Mayor Oliver Queen (Stephen Amell), who aims to clean up the streets through the legal system.
The comic book version is described as: "Adrian Chase and his alter ego the Vigilante first appeared in the 1983 New Teen Titans Annual #2. A New York City district attorney whose family was killed by mobsters, Chase sought justice in his own way. In the comics, Chase has strong ties to Deathstroke, who was a major character on Arrow."
It's further said Echo Kellum, Mr. Terrific, will be a series regular now as well.
Josh Segarra is known for Chicago PD, Sirens and Trainwreck.
Arrow Season 5 returns in the Fall on The CW.