WARNING: The following contains spoilers for Justice League: Last Ride #4, on sale now from DC Comics.
In the world of Justice League: Last Ride, the heroic team has been driven apart due to a series of major losses, the most prominent being the death of the Martian Manhunter. His demise on a mission to Apokolips to save the Earth from certain doom has remained a major conflict between Superman and Batman. The Man of Steel blames Batman for sending J'onn to his death on the mission, while Batman -- clearly hurt from the loss of his friend and teammate -- argues it was the necessary move to make.
Now, Justice League: Last Ride #4 by Chip Zdarsky, Miguel Mendonca, Enrica Angiolini, and Andworld Design has revealed the final moments of the Martian Manhunter -- and if the alien hero has to die in the line of duty, then this might be the best possible way for him to go out.
As an extended flashback to the battle on Apokolips reveals, Batman and the Martian Manhunter faced an entire army alone. While the latter held off the advance of Kalibak and his forces, Batman worked to find a way to deactivate the Boom-Nukes poised to wipe out all life on Earth. Although they couldn't shut down the bombs themselves, by draining the energy from the firepits of Apokolips they could essentially shut down the planet (and the weapons). However, to do so, someone needed to rip apart the safety hatch of the planet's core. Superman and Green Lantern were too far away to reach the core in time, and Wonder Woman's injuries -- suffered while fighting Granny Goodness and her Furies -- prevented her from being capable of performing the act.
The Martian Manhunter heroically volunteered for the job despite the fact that his innate weakness to fire meant certain death for him once the override was destroyed. Superman begged Batman to convince Martian Manhunter to not go through with the plan, but instead Batman helps J'onn by revealing the path to the core. Shaking hands, Batman apologizes for failing to find a better solution. But Martian Manhunter doesn't appear angry or saddened by what's about to happen. He bids farewell to Batman (calling him "old friend" as he does), and races to the core of Apokolips.
Wonder Woman struggles to help, but Martian Manhunter spends his last moments speaking with her and the rest of the team, telling them how honored he's been to call them both his teammates and his friends. Superman abandons Oa to try and save Martian Manhunter, but can't reach him in time. Telling them that he'll see them on the other side, Martian Manhunter rips open the core of the world. This depletes the firepits, saves the Earth -- and seemingly kills Martian Manhunter in seconds.
It's a brutal finale for the Martian hero, but also a very fitting one. Martian Manhunter has long been defined as the glue of the Justice League, so having him sacrifice himself is the perfect way to split the heroes apart. His decision to save the Earth that he openly considers his home speaks to how important the world has become to him. He's able to ensure his friends all survive, even if it means the end of him and his people. And notably, he's not even afraid. He's at peace with his choice, content with his life and his friends. It's a somber and heroic ending for the character that's definitive of the way he has chosen to live his life.