Although he's likely not popular in Amity, DC's King Shark is a hero in one of their darkest timelines, Flashpoint. Originally a Superboy villain who clashed with the likes of Aquaman, Superman, and Batman, the son of a Shark God Nananue was eventually indoctrinated into Amanda Waller's Task Force X where his size and brutal nature fit in well with the other criminals and reprobates. While he's become a fan favorite thanks to his role in James Gunn's The Suicide Squad, his Flashpoint counterpart lived a simple life working in a traveling circus where he heroically died saving others during an enemy attack.
When Barry Allen went back in time to save his mother Nora's life from being killed by the Reverse-Flash, this alteration had huge ramifications to DC's space and time continuum. Although he was successful, Barry awoke in a world that was vastly different than the one that only he remembered. Believing his old nemesis was responsible, Barry worked with Thomas Wayne, this world's version of Batman to regain his powers while the world teetered on the brink of destruction from the ongoing war between Atlantis and the Amazons led by former lovers, Aquaman and Wonder Woman.
In Flashpoint: Deadman and the Flying Graysons #1-3 by J.T Krull and Mike Janin, Richard Grayson and his parents are again part of Haley's Circus alongside acts like Doctor Fate, Boston Brand, and a half-man, half-shark who also acted as the circus' strongman. Although the performers were an enjoyable distraction for their European audience, the threat of war became more and more difficult to ignore especially as the destruction of cities by advancing armies made it difficult for booking arrangements. When the Amazonian army came looking for Doctor Fate and his mystical helmet, the performers attempted to fight back, King Shark even sacrificing himself to help Dick Grayson escape with the helm of Nabu in his possession.
Flashpoint is considered one of the biggest mistakes in the Flash's career, his selfish desire to manipulate time for his own benefit brought big changes to the DC Universe through the New 52 but was also responsible for damaging the multiverse as well according to Infinite Frontier #5. While other characters like Flashpoint's Batman would find a way to escape this universe's destruction, it became nothing but another footnote in DC history although it was one of the few times King Shark enjoyed life as a hero. Barely speaking, Nanaue appeared to be happy helping to erect tents and build stands for the circus, Flashpoint having removed any possibility of interaction with those he fought in the mainstream DC world. If anything, Flashpoint's King Shark may have more in common with the dangerous yet simple version of himself from The Suicide Squad, seeking to protect his friends at any cost.
Unfortunately, the Amazon/Atlantean war proved unavoidable and the Haley's Circus performers found themselves besieged by Amazonians in Poland. Although it would be the death of him, King Shark attempted to consume an Amazon who was chasing the survivors, her strength breaking his fearsome jaw and killing him. Although the violence seems more on par with King Shark's villainous past in another world, Flashpoint's version of King Shark died so his friends could live, another sacrifice made in a war for a world that would live on in infamy.