Warning! Spoilers ahead for King in Black: Captain America #1 from Danny Lore and Mirko Colak
In Marvel's King in Black event, the brainwashing and mind control of Captain America's best friend Bucky Barnes, aka the Winter Solider, has finally paid off. When Knull the Symbiote God began his invasion of Earth with his symbiote armies, New York was the primary incursion point, which lead to several defending Marvel heroes becoming overwhelmed and bonded into the King in Black's symbiote horde, including Captain America. Venom's son Dylan Brock eventually managed to free several heroes from Knull's control using his unique abilities to control and eradicate symbiotes, and Steve Rogers was subsequently freed from the corruption. However, Captain America is now experiencing side effects from Knull's control over his mind in a new tie-in issue, making Bucky Barnes the ideal candidate to help him overcome the trauma of the King in Black.
In King in Black: Captain America #1 from writer Danny Lore and artist Mirko Colak, Steve Rogers acts like he's totally fine after being freed from the symbiote army. In reality, Captain America is still struggling with the mental scars the infection left on his mind. It's as if Knull is still in Rogers' head, causing him to pause and have intense self-doubt about his efficacy as hero and symbol for others to rally behind. What makes it worse is that this hasn't been the only time Captain America has been co-opted for darker purpose in recent comics. Marvel's Secret Empire wasn't that long ago and saw Captain America being turned into a Hydra sleeper agent who took over the entire world. While both Cap and the world were eventually saved and restored, Rogers has still been working to make penance for those actions, and Knull takes advantage of his lasting guilt in a big way.
Still haunted by Knull, Captain America is about to give up and turn away from wielding the shield until the Falcon and Winter Solider arrive to help, encouraging him to retain the Cap mantle and keep fighting as the hero he's always been. Winter Soldier especially provides some much needed encouragement, and if anyone in the Marvel Universe knows what it's like be controlled and forced to become someone else's dark pawn, it's Bucky Barnes.
Winter Solider's words carry a lot of weight for Rogers, and it seems as though they were exactly what he needed to hear to shake Knull's influence enough for him to keep fighting the good fight. While Bucky himself is still dealing with the after-effects from his own brainwashing back when he was an unwilling assassin, it does seem as though the Winter Solider has found a way to cope and keep going as a force for good in the Marvel Universe.
Not only is Bucky Barnes one of Captain America's best friends, but he also happens to be one of the best heroes suited to help Steve Rogers recover in King in Black. Who knows? Perhaps Rogers will always be struggling with a lasting trauma from Knull's corruption. Either way, it should be a comfort for Captain America to know that he'll always have friends like the Winter Solider who have walked a similar path and will offer him support in future issues from Marvel Comics.