There are a few things that go against Superman’s moral code, but Supergirl has proven that she’s more than willing to bypass some of Clark Kent’s restrictions for a greater cause, including using her near-immortal status as a weapon.
One storyline for Supergirl sawKara save a five-year-old boy named Thomas, and promise him that he’s not going to die. However, she and Superman are soon confronted by Thomas’s furious parents, who inform Kara that Thomas has stage four brain cancer and that she’s given him false hope of survival. Superman tries to gently tell Thomas the truth, but Kara interrupts and doubles down on her promise that Thomas isn’t going to die. Over the course of the next five issues, Kara enlists help from DC's immortal hero Resurrection Man and a mad scientist to find a way to cure Thomas’s cancer, but Thomas dies before any progress is made. Even Kara’s last-ditch attempt at resurrection doesn’t work, and she has to choose between facing her failure or fighting on. Of course, Supergirl chooses to fight on, and she swears to find a cure no matter how long it takes.
Related: Supergirl Just Proved She Really is Tougher Than Superman
In Supergirl (2005) #32 by Kelley Pucketand Ron Randall, Kara faces Dolok, a time-traveling villain, fifty years in the future. Although she carries a deep hatred for Dolok, she knows that he wields a device that makes him capable of jumping back through time when threatened, potentially giving her the one tool she would need to save Thomas. During their confrontation, Dolok indeed jumps back in time multiple times, only to find Supergirl somehow always there to beat him She easily defeats him and takes his device. However, it’s then revealed that since Supergirl knew of Dolok’s
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