David P. "Dave" Ratchet, referred to as "Big Sir", is a former inmate of Iron Heights Prison that befriended Barry Allen and the late Henry Allen while in prison. Learning that Ratchet had been framed like his father, Barry unsuccessfully tried to get him exonerated. As a gesture of their friendship, however, Barry super sped Dave out of prison and dropped him off in Jiaju, China as he knew that Dave always wanted to go there.
Dave came to prison in 2003 after being mistaken for Sylbert Rundine, who killed a security guard after robbing Mercury Labs. Dave mentioned that just like in Barry's and Henry's respective trials, the jury didn't have an open mind on his innocence. He shared a close relationship with Henry Allen, who convinced the warden to allow him to perform surgery on Dave who had suffered from appendicitis leaving Dave in his gratitude. Henry himself was exonerated of his wife's murder in November 2015.
As an inmate who had previously had an altercation with Barry attempts to stab him with a shiv, Dave rushes in to save Barry and fight off the inmates, the leader of the gang assures him it is not over. Dave then told Barry he saved him as a favour to Henry for saving his life after being overcome with appendicitis. Later that day, Dave is ambushed by the gang for interfering earlier but Barry uses his speed to overpower the gang and save Dave's life.
Being given at second chance of life by Barry Allen
Barry who learned Dave's backstory and couldn't stand the injustice of another man falsely being imprisoned while the real criminal was still out there made a request to Team Flash to help free Dave. However, despite having the guy in question give a truthful but inadmissible confession, Barry still got Dave out of prison and took him to Jiaju, China where authorities wouldn't think to look for the escaped alleged convict leaving him with a note "Sometimes you DO get the movie ending" leaving Dave quite amused knowing from the note that it was Barry, the Flash, who did this for him.
- "I've been in here long enough to understand that in prison, hope is the most dangerous thing."
- —David Ratchet to Barry Allen[src]
When he first meet Barry, David is shown as a brutal person that will pick fights with others to protect Henry Allen's son. But was later revealed that it was the last time he did it since he only did so that he can pay the debt he owed to Henry showing a bit of selflessness. However, it turns out that when Barry saves his life, he admits that he will protect him longer since he deserves it.
Later when Barry tried to give him hope about the possibility to be released, he is shown to be stubborn and believes that hope is the worst thing that can happen in prison; apparently jaded in his time there, David himself admits that the notion of hoping has become entirely foreign to him until he met Barry, enabling him to experienc eit again. But he also formerly has a heroic personality as he revealed that he tried to save the dying guard that lead him into prison.
- Peak of human physical condition: Ratchet is in top physical condition. He is very strong, as seen when he curled heavy weights in the prison yard, which he used to his advantage in combat.
- Skilled hand-to-hand combatant: Ratchet had some skill in combat, as he was able to defend Barry Allen from being attacked in the prison gym.
Behind the scenes
- In the DC comics, Dufus P. Ratchet was a mentally-disabled criminal under the alias "Big Sir". He was given technological armor by the Rogues that allowed him to fly and came equipped with an energy mace.