Lyla Michaels

Lyla Michaels, known under the codename Harbinger, is a high-ranking member of A.R.G.U.S. Lyla is the ex-wife of John Diggle during his time in Afghanistan, they have since rekindled their relationship.

Background
Lyla and John met in Afghanistan, where both were serving as soldiers, and then got married. At the end of John's second tour, they rotated back Stateside, where their marriage could not survive the peace, and they divorced. John went back to Afghanistan for a third tour, while Lyla entered ARGUS.

Season 1
In "Unfinished Business", John met with Lyla rather than helping Oliver, and gave her information on Deadshot. She was shocked, as they weren't even able to find his name, and he just explained that it was for something he was working on, a lie which she could easily see through.

In "Home Invasion", When John visited the main A.R.G.U.S. building, Lyla spotted him. She scolded him for trying to use her to hunt down Deadshot, and told him to do otherwise. Sometime later, Lyla was to meet with Floyd Lawton and bring him in. However, Floyd did not show and tried to snipe her from a distance. Lyla was saved by John, who attempted to follow Floyd but was knocked unconscious.

Season 2
In "Crucible", she meets with John and flirts with him when she discovers he is single again. She gives him information about military-grade weapons being stolen. She then reveals that she is single as well to him. They part ways soon after.

In "Keep Your Enemies Closer", In the episode, Lyla is missing in Russia, having been captured during an intel operation in a Russian gulag. John is recruited to break her out, because ARGUS does not have sufficient resources for the op, and the political masters already consider her disavowed and dead to them. John arranges to get arrested and sent to the prison, where he finds Deadshot, whom he teams with to break Lyla out of jail. Returning to the United States, John and Lyla rekindle their relationship.

In "Suicide Squad", Lyla and John are enjoying a romantic interlude when they are sent on a mission by ARGUS to lead the Suicide Squad in capturing and destroying a nerve gas in the possession of Gholem Qadir. During the mission, Amanda Waller kills Shrapnel when he tries to flee. This causes a rift between Lyla, who accepts Waller's methods, and John, who objects to their brutality.

Later Lyla poses as John's bodyguard to infiltrate Qadir's party. She removes a tracking device from Deadshot in order to evade an ARGUS drone, and she and John reconcile their differences.

In a flashback sequence, Lyla is shown serving as a soldier in Afghanistan. She captures Gholem Qadir and is seen meeting John for the first time.

Season 1

 * Unfinished Business
 * Home Invasion

Season 2

 * Crucible
 * Keep Your Enemies Closer
 * State v. Queen (mentioned)
 * Suicide Squad

Comics

 * Arrow #25

Trivia

 * Lyla used the codename "Harbinger" during an A.R.G.U.S. operation to capture Floyd Lawton. In the DC Comics multiverse, Lyla operated as a superhero under this name and was a central figure of the massive comic book event known as "Crisis on Infinite Earths".
 * It is revealed in "Keep Your Enemies Closer" that she and John Diggle were married for a short time before she signed up for A.R.G.U.S.
 * In Suicide Squad it is revealed that Lyla, along with most people of A.R.G.U.S. are aware of Oliver Queen and Sara Lance's idenititys.