Albedo and Aether is such a specific pairing, isn't it? What draws me in is the absolute stillness between them, the way a story can stretch out in the quiet of a lab or a windswept mountain peak. They're both observers, in a sense. Albedo studies the world to understand its creation; Aether travels through it gathering experiences. A fanfic that gets it right uses that shared curiosity as a bridge, not for instant romance, but for a slow, methodical dismantling of their respective isolations.
You see Albedo's clinical precision bump against Aether's worn-in, practical kindness. The drama isn't in shouting matches, it's in Albedo misinterpreting a social cue because he's thinking in alchemical terms, and Aether patiently re-framing it. The best ones I've read make their intimacy feel earned through shared intellectual labor—sketching a strange flower, puzzling over an ancient mechanism. The tension comes from whether this artificial being can learn to want something for himself, and whether the eternal traveler can find a reason to stay put, even momentarily. It's less about sparks and more about two different kinds of loneliness recognizing each other's shape.
I've seen some fics try to force them into a more typical dynamic, which always falls flat. The magic's in the quiet parts.