Warning! SPOILERS for The Flash season 8 and Legends of Tomorrow season 7.
Barry Allen's efforts to save the life of the Reverse-Flash in the final chapter of The Flash season 8's Armageddon event were rendered completely pointless by a Legends of Tomorrow season 7episode, which revealed the final fate of those who run afoul of the Speed Force. Rather than being destroyed, the corrupted speedsters and their time remnants are redeemed and put to work policing the timeline. While this neatly answered the question of just how Time fixes itself in the DC Universe, it also rendered moot the moral conundrum at the heart of Armageddon's last episode.
The Flash season 8 episode «Armageddon — Part 5,» found Eobard Thawne, the Reverse-Flash, begging Barry Allen and his friends for help after his efforts to rewrite reality left him in danger of being erased from the timeline completely. This led to a long argument between the membership of Team Flash regarding the morality of allowing Thawne to die and a battle with the time-traveler Despero. In the end, Team Flash drained the speed from Eobard Thawne and sent him to a special ARGUS prison. It was a fate that, to Thawne's twisted mind, was far more cruel than simply allowing him to die. It was also, as Legends of Tomorrow revealed, a wasted effort.
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The Legends of Tomorrow season 7 episode «The Fixed Point» found the team of time-travelers trying to intentionally cause a paradox and break the timeline, as part of a plan to lure their evil robot doppelgangers (including a John Cena parodying robot Citizen Steel) into a trap. This led to the revelation that there was a subculture of time-travelers in the Arrowverse,
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