Remus Lupin loves Sirius Black.
He knows when he watches Sirius, his smoky eyes focused on the Map, the silvery fireworks his eyes become when he thinks of a new plan, the perfect prank.
He knows when Sirius taunts him for reading too much, the way his smile is teasing and warm, the way he gently elbows him, the way he touches Remus' blushing cheeks.
He knows when Sirius purposely bumps his hand, the way he holds his arm just a bit too long, the way his calloused fingers caress him, the way shivers run through him at the briefest touch.
He knows when Sirius says he loves him, the way his ebony hair falls in his face, and his voice gets quiet, gentle. The way his full lips brush his, and when they both whisper, "Forever."
And Sirius Black loves Remus Lupin too.