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[Inertia in motion - Impulse 53]
Real Name: Thaddeus Thawne
Aliases: Kid Zoom
Known “Relatives”: Bart Allen (genetic original)
First Appearance: Impulse #50 (July 1999)
Created by: Todd Dezago and others*
Death: Killed by the Rogues in revenge for setting them up.
Origin: 2980s (cloned around then)

Frustrated with his attempts to subvert his grandson Bart Allen (who would later become known as Impulse in the 20th Century), heir to both the Allen and Thawne families, to his side of the thousand-year family feud (see the Cobalt Blue Legacy), Earthgov President Thawne spliced a sample of Bart’s DNA with Thawne genetic material and grew a clone from the resulting DNA. Grown in an artificial womb, his development was slowed down by his powers, instead of accelerated like Bart’s. Every step of his physical and mental development was carefully calculated for centuries, until he reached adolescence and traveled into the past to track down and replace Bart Allen, subverting the subsequent Allen line.

Aided by future technology, including an artificial intelligence called Craydl, he first began observing Impulse, preparing for the inevitable confrontation. Their first actual encounter ended in failure, despite the fact that he has all of Impulse’s powers plus the ability to plan ahead. (Impulse #52–53, 1999)

On his second attack, armed with more research and the element of surprise, he captured and replaced Impulse, pretending to be Bart Allen for several weeks before taking an ailing Max Mercury into the Speed Force to kill him. When Bart escaped and came after them, risking his own life for the dying Max, Inertia realized he’d been nothing more than a tool for generations of Thawnes, then tore off in frustration and anger. (“Mercury Falling,” Impulse #62–66, 2000)


Inertia resurfaced after Bart became the Flash. With the speed force trapped within Bart, Inertia was powerless. As a stop-gap, he obtained an improved version of Velocity 9 from Deathstroke, but he wanted the speed force for himself. He made a temporary pact with Mota, supplying him future tech in order to lure the Flash to Inertia's own trap in the Nevada desert, then dispersed his “ally” (Flash: TFMA #5–8, 2007).

In exchange for the Velocity 9, Inertia joined Deathstroke’s team, Titans East. The mercenary had specifically designed it to take down the Teen Titans. On this team he met and developed a relationship with another time-displaced super-villain, Sun Girl (Teen Titans v.3 #43–46: Titans East, 2007).

Finally, after collecting all the data he needed, Inertia set his master plan in motion. He recruited the Rogues, promising them a world frozen in time for the plundering, but built a machine to siphon off the speed force. They placed it in the Getty Museum in Los Angeles. The Flash arrived, and the machine stole his speed. After briefly incapacitating the powerless Flash, the Rogues recognized that he and Inertia were related, and realized they had been played for a personal vendetta. Fearing that the Flash would regain his powers, they attacked and killed him. It’s not clear whether Inertia participated in the final attack or was incapacitated at the time (Flash: TFMA #10–13: Full Throttle, 2007).

Full Stop

When Wally West learned of Bart’s murder, he was temporarily so in tune with the speed force that he stole all of Inertia’s speed. The Flash left the young Thawne frozen in place as a statue in the Bart Allen wing of the Flash Museum (All-Flash #1, 2007). Meanwhile the Rogues were hunted down and sent to a hell planet (Countdown, Salvation Run, 2007–2008).

[Kid Zoom in Rogues' Revenge #3] Zoom restored Inertia’s speed and taught him to draw on his time-based power — and insisted that he become the new Kid Flash in order to make up for his crime. Inertia went along at first, unaware the the Rogues were on his trail, out for revenge. During a confrontation with the Rogues, Pied Piper, and Libra, he apparently killed Weather Wizard’s son Josh in a hostage stand-off, then declared that he was “Kid Zoom” and would dedicate himself to causing tragedy. His first act: stealing time from Zoom, to make him the cripple he had been before gaining his powers. In the subsequent battle, Piper stunned him, and the remaining Rogues ganged up on Inertia and killed him (Final Crisis: Rogues’ Revenge, 2008).

Text by Kelson Vibber. Do not copy without permission.

Top of Page Primary Sources

  • “Threats” - Impulse #53 (October 1999), Todd Dezago


  • Inertia: Impulse #53 (October 1999) - some combination of Walt Simonson, Angel Unzueta, Scott Williams, and Keith Williams
  • Kid Zoom: Final Crisis: Rogues’ Revenge #3 (November 2008) - Scott Kolins


  • The Flash Companion (2008)

Significant Legacy-Era Appearances

  • Impulse #50–51 (July–August 1999): “First Fool’s” and “It’s All Relative,” Todd Dezago (observing)
  • Impulse #52–53 (September–October 1999): “Tumbling Down” and “Threats,” Todd Dezago
  • Impulse #62–66 (July–November 2000): “Mercury Falling,” Todd Dezago

Significant One-Year-Later Flash Appearances

  • The Flash: The Fastest Man Alive #5–6 (December 2006–January 2007): “Lightning in a Bottle, Parts 5–6,” Danny Bilson & Paul DeMeo
  • The Flash: The Fastest Man Alive #7–8 (February–March 2007): “Speedquest,” Danny Bilson & Paul DeMeo
  • Countdown #46 (June 2007) Paul Dini (head writer) with Jimmy Palmiotti & Justin Gray
  • The Flash: The Fastest Man Alive #10–13 (May–August 2007): “Full Throttle,” Marc Guggenheim
  • All-Flash #1 (September 2007): “Justice, Like Lightning,” Mark Waid
  • Flash #241 (August 2008): “Fast Money Part 4: Flash Mob,” Tom Peyer
  • Final Crisis: Rogues’ Revenge (3-issue miniseries, September-November 2008), Geoff Johns


* On creating Inertia, Ethan van Sciver wrote on the Comic Bloc forums in July 2006:

I wouldn’t accept credit for that. I think if a pie chart were made of who created Inertia, is would be built of these percentages:

Grant Morrison: 25%
Todd Dezago: 50%
Mike Weiringo (who designed the original Impulse costume, which was reversed for the sake of Reverse Impulse) 20%
Me: About 5%, for making him green and black, and giving him blonde hair.

It’s not clear where Grant Morrison fits in.

The Flash Companion The Flash Companion
Preview at Speed Force
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