After entering the central multiverse, The Red Death infected Central City with a Speed Force Storm which gave him the ability to accelerate aging in other people to the point of death and attempted to use this ability on Barry Allen's loved ones but was stopped by Barry as the Flash.
In the comics, Red Death is a version of Batman from an alternate universe that lost the battle against Gotham's villains, so he went bad and went after the Flash to become the Speed Force's avatar. In The Flash series, however, the character is pretty similar, but it's not Batman – it's a version of Batwoman.
After playing the supervillain Red Death for multiple episodes in The Flash's final season, Leslie's original Arrowverse character Ryan Wilder a.k.a. Batwoman returned in Wednesday's "The Mask of the Red Death, Part 2" to help Barry (Grant Gustin) and the rest of Team Flash defeat her evil doppelganger.
In DC's comic universe, Red Death is an alternate evil version of Bruce Wayne who absorbs the Flash's powers using the Speed Force. On TV, at the end of the episode, Red Death removed their helmet, revealing it to be an evil version of Ryan Wilder, a.k.a. Batwoman.
Instead, this version of Red Death in this season of The Flash is Ryan Wilder from another Earth where she was adopted by the Waynes. Though Red Death isn't Bruce, it's still refreshing to see a female villain in the mix, especially one played by Javicia Leslie who returns to the Arrowverse.
Wally West is the Fastest Flash and is arguably the fastest being that has ever existed, as said by Max Mercury—and it has been remarked that Wally and Barry are the only two speedsters that were fast enough to even outrun death itself.
The ninth and last season of The Flash will see the titular hero taking on his final antagonist, the dangerous DC villain Cobalt Blue.
Considered impossible on all levels, outrunning death is a feat that no one but Wally West has ever accomplished. Not only did he outrun his own death, he also outran the death of the entire DC Universe in The Flash #141 by Mark Millar, Pop Mhan, Joshua Hood, Chris Ivy, Tom McCraw, and Gaspar Saladino.
Doctor Strange is a Master of the Mystic Arts who wields a number of powerful spells and artifacts, making him a dangerous threat. Beating the Flash as simple as Doctor Strange moving the battlefield to another dimension or changing into one of his more powerful forms.
The Black Flash appeared to the fourth Flash, Bart Allen, immediately before his death at the hands of the Rogues at the Getty Center. Barry Allen later became the new Black Flash after the old one was found "apparently dead".
Episode 3 ended with the surprise twist that Red Death isn't Bruce Wayne at all, but rather the current Batwoman, Ryan Wilder.
When Flash refused, Batman strapped him to the hood of the Batmobile, and basically gunned it until their bodies fused together into one. Although Flash had lost his body, his consciousness remained dormant inside Batman's, and at the end of Dark Knights managed to regain control and destroyed the Red Death.
In their attempt, the Red Death is exposed to an intense blast of the positive energy of creation from the baby universe, reversing him. This creates a Reverse Flash (just like the Flash's nemesis in the main DC Universe) out of the Red Death — turning him into a good guy.
The Red Death is an enormous Stoker Class dragon that first appeared in How to Train Your Dragon.
Their speed is probably equal. However, Red Death is overall stronger than the Flash, Red Death is the usual Batman, but with the speed force, he has the whole abilities of Batman and the speed of the Flash, and most importantly, this Batman is bloodlusted.
The Black Flash is a fictional comic book character from DC Comics. Created by writers Grant Morrison and Mark Millar, and artist Ron Wagner, the character had cameos in The Flash vol. 2 #138 (June 1998), before appearing in full in The Flash vol. 2 #141 (September 1998).
Superhuman Durability: Black Flash is capable of withstanding high levels of physical harm, and suffer no injury. Superhuman Speed: The Black Flash can move at vast superhuman speeds, surpassing even Barry Allen. The Flash has described it as faster than anything he has ever encountered.
While Eobard Thawne is the fastest villain Flash has ever faced, Black Flash is the fastest speedster of all time. This being is Death for anyone who possesses the power of the Speed Force. When he shows up, someone is about to die, as seen in the cases of Barry Allen, Johnny Quick, and Bart Allen.
Creators. Malcolm Thawne is the lost twin brother of Barry Allen. He is a Cobalt Blue, one of a number of evil counterparts of the Flash that wields the Blue Flame.
Rag Doll. By far the creepiest metahuman Team Flash has encountered was Peter Merkel's Rag Doll. Created on the night of the Enlightenment, Peter was crushed by pieces of the destroyed satellite.
Wally has stated numerous times that Barry is the faster Flash between the two of them, which makes sense considering that Barry beat himself in a race.
With Barry, Wally is faster than him and for Wally, the only person who has ever been faster than him was Zoom but Wally was able to figure out how to overcome the villain's advantage.
God of Death Flash
This version of Flash is among the most powerful since it's an aspect of death, a primordial force, or whatever you call it, that no one can escape from. God of Death Flash came into existence when Black Racer and the Flash merged in order to defeat Darkseid.