The following contains spoilers for Marvel's Midnight Suns' The Good, the Bad, and the Undead DLC.
Marvel's Midnight Suns has been an incredibly huge success, with the tactical game conjuring up fantastic sales figures and reception. Many gamers may have already beaten its story a few times over, but thankfully, DLC has been in the works since the game's inception. The first batch of add-ons introduces everyone's favorite Merc with a Mouth, as well as one of Captain America's most sinful enemies.
Sin is the main antagonist of The Good, The Bad, and the Undead DLC, and while she's been radically changed to fit the game's scope, fans of the Sentinel of Liberty should recognize her. Her comic book backstory influences her powers in the game, making the vampiric villain a powerful enemy of the Midnight Suns. Here's who Sin is in the comics and how she relates to Steve Rogers' arch-villain, Red Skull.
Sin Is the Daughter of the Red Skull in Marvel Comics
Debuting in Captain America #290, Sin was created by J.M. DeMatteis and Paul Neary. The daughter of Johann Shmidt, AKA the Red Skull, the young girl was almost killed by her Nazi father due to her not being the male heir he desired. Spared from this fate, she was given the name Sinthea Shmidt and indoctrinated with her dad's poisonous worldview. She would later be artificially aged and given superhuman abilities as Mother Superior, leading a group called the Sisters of Sin made up of similarly aged women. In this role, she had powers such as intangibility, teleportation, and psychic abilities.
Later reverted to her normal age and robbed of her powers, Sin would grow older naturally, working alongside her father while developing a relationship with Crossbones. This took place during the acclaimed Ed Brubaker Captain America run, with Sin rising to much greater prominence throughout its entirety. She would lead a new version of the Serpent Society and torment Sharon Carter, making her into a far bigger deal than she had been in the past. During the Fear Itself story arc, she almost lived up to Red Skull's ambition by using the lost hammer of Skadi to become more powerful than ever before. Thankfully, she was defeated when Odin stripped her and others of their powers, with this development being her last true place of prominence outside a smaller role in Secret Empire.
Sin Is a Radically Different Villain in Marvel's Midnight Suns
Introduced in the DLC, the version of Sin in Midnight Suns differs greatly from her comic book counterpart. For one, she leads the game's newest enemies, the Vampyres, giving her a far more supernatural aspect than usual. Her appearance and vampire powers are arguably similar to those in her time as Mother Superior, but she's otherwise far removed from her more street-level origins. Likewise, the game changes her origin story to being the Red Skull's granddaughter rather than his daughter, which makes a lot of sense given that Johann Shmidt operated during World War II, and Midnight Suns is set in the present day.
The ending of the DLC's storyline reveals that Sin is actually working with Dracula, once again filtering the characters through a supernatural lens. Given that much of the focus of the game and the DLC is on Blade, the Vampire Hunter (who was also a part of the original comic book Midnight Sons team from the '90s), this focus on bloodsucking children of the night is logical. Likewise, it also gives Sin enough of a power boost to be a major threat on her own, requiring more than just Captain America's shield to take down. Given how popular the game has been since its release, Midnight Suns is providing Sin with more exposure than she's ever had, even as a DLC villain.