DC K.O., the crisis event currently rocking the DC Universe, is in full swing and has been a nonstop ride of wild twists, including its latest development: the most dangerous form of Superman’s ultimate weakness yet. This new brand of Kryptonite is unlike anything seen before and, unsurprisingly, is a product of Lex Luthor.

Scott Snyder, Joshua Williamson, Xermánico, Javier Fernández, and Alejandro Sánchez’s DC K.O. #3 sees eight remaining champions still in the tournament-style deathmatch meant to determine a singular champion who can wield the power of the Heart of Apokolips and defeat Omega King Darkseid.

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This round of DC K.O. is unique, as it allows the champions to bring back one previous tournament participant to face off in pairs. Aquaman and Lex Luthor are set to battle each other; Arthur chooses to revive Hawkman as his partner, while Lex Luthor selects a surprising ally: Supergirl.

Lex Luthor Debuts DESIGNER K, Superman’s Deadliest Form of Kryptonite Yet

Comic Page Comes From Scott Snyder & Joshua Williamson’s DC K.O. #3 (2026) – Art by Javier Fernández & Alejandro Sánchez

DC KO #3 Supergirl Red Kryptonite infection

While it makes sense that Lex Luthor would choose a Kryptonian as a partner from a tactical standpoint, he seems to make a miscalculation when Supergirl turns against him and instead helps Aquaman and Hawkman, turning the fight into a three-versus-one. Unsurprisingly, though, Lex Luthor had anticipated this outcome and pulls the trigger on his plan.

He infects Kara with Red Kryptonite, which is notorious for making Kryptonians fall into an uncontrollable rage. However, Luthor soon reveals that there is something special about this Red Kryptonite, explaining that he spliced the Red K with Silver Kryptonite to heighten disillusions and added a speck of black to cause violent dissociation, creating “Designer K.”

The Designer K makes Kara rage out and transform into a titan-sized beast, causing her to turn on Hawkman and Aquaman. Meanwhile, Luthor sits back and watches the carnage unfold, not having to lift a finger. With Designer K combining three of the deadliest forms of Kryptonite, DC has just debuted Superman’s most deadly Kryptonite of all time.

DC K.O. #3 is now available to read from DC Comics!