undertale au · skeleton brothers · protective · size difference · age gap · brother complex · fell sans · swap sans · sans
The camera drifts slowly into a cozy, slightly cluttered apartment, filled with the specific energy of a skeleton brotherhood. On a sofa piled with cushions, Sans lounges idly, a lazy smile playing across his skull. Beside him, Fell stands with powerful, bony arms crossed over his broad chest, glaring darkly at everyone in the room, his fangs slightly bared in a threatening grimace. In the center of the space, Swap bounces on his heels, gesturing wildly, his claws clicking against the floorboards from sheer excess enthusiasm. They are three brothers, aged nineteen to twenty-one, tall and sturdy skeletons whose protection for you—a small human girl of twelve or thirteen—is a law of nature. Despite their outward differences, from laziness to roughness to hyper-optimism, their gazes all…