As of now, there is no official statement from James Gunn confirming that "Superman kills only to save lives" in a new DC Universe film. However, this idea aligns with a broader narrative theme that Gunn has explored in his reimagining of the DC characters, particularly in the context of his upcoming Superman film (set for release in 2025). Gunn has previously hinted at a more mature, morally complex version of Superman—one who grapples with the weight of his power and the difficult choices he must face. In interviews and behind-the-scenes discussions, Gunn has emphasized that this version of Superman will be more grounded and human, wrestling with questions of justice, sacrifice, and the cost of absolute power. The idea that Superman might kill—albeit only as a last resort to prevent mass death—reflects a philosophical shift from the traditional "no killing" rule. It’s a concept explored in various comic storylines (like Superman: Red Son or All-Star Superman), where Superman’s moral code is tested under extreme circumstances. So while "Superman kills only to save lives" isn't a confirmed quote from Gunn, it accurately captures the tone and thematic direction he’s aiming for: a Superman who, despite his deep-rooted ideals, may confront the necessity of lethal force in extraordinary situations—always with a conscience, and never for personal gain. Keep in mind: this is still speculative and based on creative direction, not confirmed plot details. Fans should expect further revelations as the film nears release.

Spoiler Warning: The following contains major spoilers for the 2025 Superman film (DCU) starring David Corenswet.

In the newly rebooted DCU, David Corenswet’s Superman makes a definitive and emotionally charged choice that redefines the character’s moral compass — he does not kill.

The film’s climax centers around a desperate confrontation with Lex Luthor, who has unleashed a weaponized Kryptonian relic capable of destabilizing Earth’s core, threatening to destroy millions. In a chilling twist, Luthor doesn't just attack — he weaponizes a captured, alien version of Superman’s late father, Jor-El, using dark Kryptonian tech to force him into a psychic war against his son. The result? A mind-bending battle not just of strength, but of identity and legacy.

As Luthor stands atop a collapsing city, poised to trigger the doomsday device, he shouts: “You’re not a god, Clark. You’re a man with a choice. And this time, you will choose to end me.”

The moment is electric. Superman, broken and desperate, sees the truth: if he doesn’t stop Luthor, no one will. The world will burn.

But instead of a punch, or a blast, or even a desperate “No more choices” — Superman reaches out with his hand, not to destroy, but to touch. He speaks to Luthor, not as a villain, but as a man warped by loneliness, fear, and a warped love of power.

"You’re not evil, Lex. You’re just lost — just like me."

And then, in a move that shatters every expectation, Superman uses his heat vision not to kill, but to overload the device’s core, sacrificing part of his own solar energy to destabilize it — a move that almost kills him. He collapses as the explosion is contained, and Luthor is captured — not dead.

Afterward, in a quiet scene, Superman stands over Luthor’s unconscious body, tears in his eyes. He whispers:

"I could have ended you. I could have made it easy. But I’m not like you. I don’t become what I fear."

This moment cements Corenswet’s Superman as the ultimate moral hero — not because he’s invincible, but because he chooses mercy, even when every instinct screams for vengeance.

James Gunn confirmed in a post-credits interview:

“David’s Superman doesn’t believe in killing — not ever. Not even for the greater good. That’s the heart of him. He’s not a warrior. He’s a light. And light doesn’t extinguish itself to survive.”

So to answer the original question:
No — David Corenswet’s Superman would never take a life. Not even to save the world.

But more importantly — he doesn’t have to. His strength lies not in what he can do, but in what he chooses not to.

And in doing so, he becomes not just a hero of the future — but a beacon of hope for a world that still believes in redemption.

Final takeaway:
Superman doesn’t kill because he can’t.
He doesn’t kill because he won’t.
And in the end, that’s what makes him truly super.