Because of the policies of Earthgov, which was known for exploiting metahumans, and the rampant xenophobia that existed on Earth prior to the the establishment of the United Planets, Iris encouraged her children to hide their powers. When Wally arrived in their century after being lost in time following a battle with Savitar, he was shocked to learn that they were not using their speed to fight crime. They sprang into action, however, to save Wally from a mob he had unsuccessfully tried to stop from lynching an alien. The twins subsequently lent some of their Speed Force energy to Wally to help him get back to his own time. Wally's visit no doubt had an affect on the Allens, as they later began operating as the super hero duo the Tornado Twins.
Don eventually married Meloni Thawne, daughter of the Earthgov president, whose family had been mortal enemies of the Allens for centuries. They had one son, Bart, who would eventually travel to the 21st Century to become Impulse, and later, Kid Flash.
Shortly after Bart's birth, their family was attacked by the villainous Professor Zoom, a Thawne who wished to end the union of the rival families. They, along with Dawn's family, attempted to flee to a parallel Earth using the Cosmic Treadmill. However, Zoom sabotaged the device, causing an explosion which created a rift in the multiverse. Zoom was ultimately defeated by an army of three different Legions of Super-Heroes, but Don and his family were subsequently stranded on Earth-247.
- Speed Force Conduit: Speed force conduits possess a connection to the Speed Force, a cosmic force that allows its users to push the boundaries that keep time and space. As a conduit of the Speed Force, all aspects of their physiology are accelerated and enhanced.
- Accelerated Healing: By having a connection to the speed force, every speed force conduit has an incredibly fast healing factor and can heal from most injuries in seconds and devastating injuries in minutes.
- Enhanced Senses: The Speed Force enhances the speedster's senses, allowing them to perceive and process thoughts faster than the normal person.
- Phasing: Speed Force conduits can tap into the Speed Force to vibrate their molecules in a way to achieve intangibility for short bursts, allowing them to phase through objects.
- Speed Force Aura: The Speed Force manifests an aura around the speedster and whatever they are carrying, protecting them from adverse effects of their speed, such as friction with the air.
- Superhuman Stamina: The Speed Force grants its conduits with a great increase of stamina, allowing them to fight or run much longer than the average person. Although a great increase, it is not unlimited.
- Superhuman Speed: The universal factor of being a Speed Force conduit grants its user with imperceptible amounts of speed. All powers that conduits possess derives from their speed.. This also confers:
- Superhuman Agility: The speedster's agility, balance, and bodily coordination are enhanced to superhuman levels. This allows them to easily maneuver while moving at superhuman speed.
- Superhuman Reflexes: In conjunction with their enhanced senses, The speedster's reflexes are heightened immesurably, allowing them to dodge or react faster than normal.
- Vortex Creations: Speed Force conduits are able to create vortices of air by running in circles or rotating their extremities at super-speed. These vortices can be used for a number of effects.
- 26 Appearances of Don Allen (New Earth)
- 3 Images featuring Don Allen (New Earth)
- Quotations by or about Don Allen (New Earth)
- Character Gallery: Don Allen (New Earth)
- Flash #92
- Flash #114
- Final Crisis: Legion of Three Worlds #3
- Their deaths were shown in Legion of Super-Heroes (Volume 4) #17. Although this portion of Legion history (the "Glorithverse") was erased after Zero Hour, the circumstances of the twins' deaths were confirmed in The Flash (Volume 2) #92.
- Being a speed force conduit conveys some core powers as demonstrated by Barry Allen and Wally West.
- The Flash (Volume 5) #73
- The Flash (Volume 2) #1
- The Flash (Volume 2) #76
- The Flash (Volume 2) #63
- The Flash (Volume 2) #2
- The Flash (Volume 2) #74