The Red Room built Natasha, patiently and carefully and mercilessly, and it built her to be patient and careful and merciless herself, to know how to build and how to destroy.
The things she'd been supposed to know how to build were all shadows, all deceptions and facades, just as the Red Room had built her to be a shadow only, nothing like fully human.
She was built well, but maybe too well, or maybe there'd been a crucial mistake in their blueprints. Maybe they hadn't been merciless enough; she would have said that was impossible, once upon a time, but she'd seen a few things since then. In some way, somehow, everyone is ultimately more fortunate than they might have been.
The things she'd been supposed to know how to destroy were everything; anything that was required. This truth had not changed.
It's been years since she belonged to the Red Room in any way. She's still patient, still careful; she's merciless when necessary. She knows conserving resources is always important, but sometimes she builds things just to remember – her skill set is wider than her designers meant for, and she is more than a shadow herself.
Metal shaped with heat and touch into her favorite pair of earrings; a cup of coffee she drinks with Pepper Potts after a day that only ends long into the evening. Clint's casually thrown glance over a battlefield, carrying the absolute certainty it will be understood. Her hand on a headstone she comes to see, despite knowing the dead do not wait in cemeteries, the terrified faces of people who have yet to fully realize they will live another day – the things you build, and help to build, and which build you in return, one more step away from the original layout.