WARNING: The following article contains spoilers for The Flash #79 by Joshua Williamson, Rafa Sandoval, Arif Prianto and Steve Wands, on sale now.
All throughout the current Flash story arc, "The Death of the Speed Force," the various Force users were being pursued relentlessly by the Black Flash, the Speed Force's personification of death. The monstrous speedster had long thought only to hunt those directly connected to the Speed Force but, with other secret Forces now active in the DC Universe, Black Flash hunted any figure serving as a Force avatar, able to track when those powers were being tapped into.
As the Still Force user Steadfast used his powers to help restore Iris West's pre-Flashpoint memories about her nephew Wally, Barry Allen senses the arrival of a speedster interrupting the proceedings. However, the attacking figure isn't the Black Flash but someone particularly unexpected: Hunter Zolomon.
Zoom, one of Wally West's greatest enemies and his incarnation of the Reverse-Flash, had last been seen prominently during last year's epic storyline "Flash War." The villain had subtly maneuvered Barry and Wally into a volatile confrontation, estranging the two lifelong friends and superheroes with the revelation that Wally's family had been lost by the reality-altering events of Flashpoint and the New 52.
In a desperate attempt to regain his family, Wally sought to run fast enough to rupture the Speed Force where he had been trapped after Flashpoint, with Barry racing after him to stop him. Ultimately, the two inadvertently broke the barriers between the various Forces which had long lay dormant while Hunter took the opportunity to strike from the shadows and gain a greater connection to the Speed Force than either Barry or Wally, effectively making Zoom the fastest man alive (for a little while.)
Hunter revealed he had traveled to the far-future where he discovered the existence of the other Forces from history books covering the relative present of the DC Universe. In addition to the Speed, Strength and Sage Forces, one of the most elusive, mysterious Forces is the Still Force, which even Hunter couldn't learn much about during his time in the future.
With Steadfast making himself known by using his powers, even for just a moment, he effectively made himself a target to both the Black Flash and Zoom, the latter of whom swoops in to pluck him away to parts unknown as Barry and Iris watch helplessly in this issue.
What exactly Hunter intends to do with Steadfast is currently unknown but, given the villain's recent obsession with the Forces, he may be attempting to unlock further powers to become more than just the Fastest Man Alive in the DCU. Before Barry can react, however, all of the activity involving the Speed Force and Steadfast has indeed alerted the Black Flash, who is seen ominously running right towards Barry as he attempts to regroup and follow the speedster villain.
Hunter Zolomon is the most personal enemy that Wally West ever faced, with the friend-turned-foe nearly claiming the lives of Wally's unborn twins by attacking a pregnant Linda Park in a twisted effort to make Wally a better hero by instilling great personal tragedy. By the start of DC Rebirth, Hunter was more interested in becoming a superhero himself, dissatisfied with Barry Allen and Wally's efforts as the Flash, leading to his own connection with the Speed Force.
With the revelation that the death of a Force user makes the remaining ones stronger, Hunter has likely received a boost through his connection to the Speed Force. Whether Zoom intends to kill Steadfast to further augment his speed or study him to learn more about the Still Force, neither possibility bodes well for the Flash as the evil speedster continues to stay one step ahead at the worst possible time for Barry, with the Black Flash active and not far behind.