Black Widow: 10 Insanely Dark Moments That Won’t Be Used
9. When She Killed Her Brother
With the relative lack of awareness of the 1998 Shadows and Light Marvel series, it makes complete sense that one huge detail about Black Widow has fallen to the wayside; the small detail of her having brothers.
More importantly, it also means you miss the fact she's also killed at least one of them, as when Natasha reunites with one of said brothers, he reveals that he has intense resentment for Black Widow being the only member of the family to escape a house fire, and - in true 'secret evil sibling' form - has spent his adult life as the 'Vindiktor', trying to hunt down and kill the assassin.
Not only are Marvel unlikely to include this moment in the MCU because secret family members are the most overplayed trope ever, but also because Natasha's coldness towards her suffering family members makes her a significantly darker hero than her film universe counterpart.