Jonathan and Martha Kent are the adoptive parents of Kal-El, with both of them appearing in the prequel comic for Injustice: Gods Among Us.
Jonathan and Martha Kent are the adoptive parents of Superman, also known as Clark Kent. Since they were unable to conceive a child of their own, when the Kents found him as a baby inside of a strange rocket crashed to Earth they raised him as their son. Much later they learned he was the last surviving member of an alien race; when the planet Krypton was exploding, the boy's parents Jor-El and Lara chose to save him at the cost of their lives by sending him into space. Ma and Pa Kent raised Clark on their farm in Smallville, Kansas. They were caring parents who instilled him with a deep sense of morality. Eventually he began developing powers and they helped him create the alias Superboy. Although their boy grew up and moved to the bustling city of Metropolis, he would still frequently visit them.
During Chapter Seven, the President of the United States hires Mirror Master and a team of commandos to kidnap Jonathan and Martha Kent in order to use them as bargaining chips to hold over Superman in an attempt to force him to cease his enforced peace-keeping and to stop him from becoming involved in government business. Mirror Master breaks into the Kent farm and attacks Jonathan and Martha in their sleep. Jonathan puts up a struggle after Martha is yanked out of bed but he is easily subdued by Mirror Master's men. Jonathan and Martha's home is then torched and they're forced into Mirror Master's mirror dimension.
Later, the Justice League learns of their kidnapping, and after interrogating several of the Flash's Rouges, they learn Mirror Master's location and force him to reveal where he's keeping them. The Kents were being held in Bolivia, specifically Salar De Uyuni, the world's largest natural mirror. Superman uses Mirror Master's own technology to free his parents.
Though absent for several chapters, the Kents reappear in Chapter Twenty-Six, having been taken to their son's Fortress of Solitude and spent the last month there in complete safety.
They witness Lex Luthor's completion of the super-soldier pill and Jonathan Kent questions him on whether or not he should be proud of himself for it. Though Lex is, Martha tells him that Clark needs someone to talk to and not some superscience pill. Lex tries to convince them that their son is doing something beyond their comprehension, though the Kents refuse to hear this and insist their son is in pain and is trying to retake control after losing Lois and Metropolis.
Martha then tells Lex a story of when Clark was a young child, and the first time he used his super strength was after he lost a blanket he loved and punched over a tractor during a tantrum. When an incredulous Lex then asks if they're calling Superman a scared child, Martha asks with a gentle smile, "Aren't we all?"
When Lex asks if they think this is a "super tantrum" Jonathan tells him this goes way beyond that and asks if Lex is really the smartest man alive if he can't tell that Clark needs help. Lex is silent as Martha explains that Clark is still just a man despite all his abilities and that he can make mistakes.
After Lex explains his reasons for believing in Superman, Martha asks him if he feels guilty for surviving Metropolis, and Lex admits he does. Martha then has Lex look around the Fortress, explaining that Clark lived through his birth parents deaths, his planet's destruction and now the loss of his wife and city. Martha says that Clark couldn't live with himself if he lost anything else.
Jonathan adds that Clark is keeping them in the Fortress because he thinks they'll be safe there, but he fears his son will try to put the whole world in his Fortress. When Lex asks him what he wants him to do, Jonathan just asks him to do what's right. Jonathan goes on to say that Lex has created the means to put the power back in the hands of the common people. He asks Lex that on the day that the world needs to be saved from his son, he asks that Lex find a way to save Clark.
The Kents reappear at the end of Chapter Thirty-One, shocked to see Batman and his team of Insurgents break into the Fortress. Martha calls Bruce by his name while Jonathan suggests he leave. Batman tries to comply, but an enraged Superman arrives shortly after, grabbing Captain Atom by his neck as he angrily glares at Batman.
In the next chapter, both Jonathan and Martha try to calm Clark down, but when this fails, Captain Atom blasts Superman, causing the Man of Steel to fly through the ceiling, partially collapsing the entrance to the Fortress, leaving the Kents trapped inside with Green Arrow.
In Chapter Thirty-Three, the Kents are still inside the Fortress with Green Arrow when Superman returns, breaking through a wall to access the main chamber where they are. Martha is horrified to see how injured Clark appears after his battle with Captain Atom. When Superman dangerously advances on Green Arrow, Ollie fires an arrow in an attempt to distract Clark, but the shaft bounces off of his invulnerable frame and impales Jonathan in the shoulder.
Infuriated, Superman then brutally attacks Green Arrow, pummeling him to death despite Martha's pleas for him to stop.
Superman continues to bludgeon Ollie's corpse, forcing Martha to take one of the nanotech pills to get the strength needed to catch Clark's next punch, stopping him. Clark is momentarily surprised before realizing she took one. Martha explains it was the only way to stop him. Clark is horrified when he realizes one of the pills is missing and starts to leave, shocking his father, who needs medical attention for his arm.
Superman tries to explain the danger of letting Batman manufacture the pills but Jonathan angrily asks, "What the hell is wrong with you?" Superman tries to say he doesn't have time to help him but Jonathan insists he does. Their argument is interrupted by the arrival of Jor-El's program, who admonishes Kal-El for committing murder in the Fortress.
Jonathan looks at Ollie's body before asking his son if Ollie had been his friend. Superman tries to rationalize his actions by using Jonathan's injury but Jonathan understands that Ollie hadn't intended to hurt him. Superman suddenly declares the entire situation Batman's fault, though Martha tries to convince him it isn't Bruce's fault but Kal-El refuses to listen to his parents.
Martha pleads with Clark, trying to remind him that Bruce is his friend and begs him not to take his life. Clark ignores her words and flies out of the Fortress. Martha looks towards the devastated Jor-El and says, "We tried...we tried to raise your son. We're so sorry." Jor-El looks back at her and apologizes for unleashing Kal-El on their world.
The parents of the Man of Steel stand in the Fortress alone, with Jor-El silently offering comfort to the Kents.