She first saw him when she was 22 years old, and injured on a mission. He was 10 years old, and visiting an aquarium. Percy Jackson looked into Natasha Romanoff's weary but determined eyes, and decided to help her. And so, he pulled a lever, spilling his class and her enemies into a tank. That was not the last she saw of him. By the time several years pass, the two green-eyed siblings by bond will be known as heroes, albeit of different worlds. Perhaps they don't know everything about each other. But they do know that they will always have each other's backs. He helps her out when her missions don't go the way they planned, which doesn't happen too often. She teaches him how to be a good spy, although that isn't the intention when they start the lessons. And they become very close, just as close as true siblings, in fact. So when Natasha finds herself in a complicated position during the Avengers' Civil War, Percy decides to interfere. And the Avengers are extremely surprised when they meet Natasha's younger brother. Plans are made and set in motion, alliances are completely misconstrued, friendships are tested and broken, and the two siblings find themselves on their own side against the world. However, there's something bigger in the works for the Avengers, and they'll need all the help they can get to face it. Including the two green-eyed siblings in everything but blood. This is largely Marvel canon compliant up until Captain America: Civil War, with Percy's interaction with Natasha being a background to the PJO books. Cover by @cajoling - she's awesome, honestly I'd check out her work as well lol

Red: She loves the color, but hates it at the same time. It's splashed in her ledger, dripping from her fingers. Red will always be a part of her. It shaped her, defined her, molded her from a young age. She doubts that she will ever escape it. It is the color of her hair, after all. As a child, she learned to leave a trail of red in her path wherever she was sent. Now, it's a bit different. Now, he tries to help her see the good in herself. He and the kid. But she knows he can't help her until he sees the good in himself as well. Red represents her as a person. Whether Red is actually good or bad; well that's the question, isn't it? Green: He sees this color every night in his dreams. He sees it as he rips his life apart, succumbing to the raging anger inside of him, letting the monster out. He sees it as he loses control, feels unimaginable pain as he changes form, knows it precedes destruction. But he sees it in her eyes as well, a vibrant green, the color of spring. Full of hope and determination. The kid's eyes as well. Sea-green and strong. She tells him that green's good. Green represents life, rebirth. She says that green doesn't have to mean destruction. But can Green be associated with such positive things for long? Blue: The color reminds him of happier times, when his life was uncomplicated, and full of love. Back when his mother baked him cookies dyed just the right shade of it, when it was a symbol of rebellion. Now, it's a bittersweet memory. They call him a hero. But he knows he's dangerous, always part of a prophecy of some sort. And he's no hero. The friends he's lost are proof of that. Two wars, and so many lost, the love of his life being one of them. He has to move on. He promised. The color is painful for him now, but he stubbornly keeps it around as a reminder. How can he remember all the good times he's had, if Blue only makes him think of the bad? Or: Three heroes form a mini team and help save the universe. Does anyone expect it? Nope.