Who is he?
Barry Allen is the main protagonist of the CW show, The Flash. He first appeared on Arrow, of which Flash is a spin-off. After he went to Starling City to investigate a case, he found out Oliver Queen was The Arrow and got acquitanted with him, John Diggle, and Felicity. After that he returned to Central City, where he was struck by lightning from the particle accelerator explosion and was in a coma for 9 months. After he wakes up, he founds out he has the power of superspeed now. After finding out that there are others like him, he goes to Oliver for advice, and Oliver tells him that he thinks the lightning chose him, inspiring Barry to become a hero.
Barry has been willing to sacrifice his life to save everyone else on multiple occassions. Most recently in the Crisis on Infinite Earths crosssover event, where he was told he was going to die and he accepted that. Previous examples of that include when he went to the Speed Force to stabilize it at the end of Season 3 and when his time remnant sacrificed himself to save the multiverse from Zoom's machine at the end of the Season 2.
On certain occssions, when a family member of his is hurt, Barry has been willing to murder his enemies. In Season 2, after his father was killed by Zoom, he originally wanted to torture and kill him, although he did not end up doing that in the end. In Season 5, after his future daughter was injured by Cicada, he was going to kill him, if not for her showing up and convincing him not to do it. In Season 3 episode 21, after finding out Savitar's identity, he tries to snap his neck. Furthermore, Savitar, who is the Season 3 villain, is a future version of Barry. He is a time remnant, which is something that occurs, when a speedster travels back in time a few seconds ago and then their past self does not time travel, the past self becomes a time remnant (which is basically saying that they should not exist anymore, but they do to preserve the timeline). After that he was abandoned by all of his friends for not being the "real" Barry, which drove him mad and eventually led to him becoming Savitar.
I think it should be an easy cut, especially considering the guy had to fight an evil future version of himself once.