This is really a crossover piece between FMA and the book (or movie) The Golden Compass. You could also it corresponds to the entire His Dark Materials trilogy, but I haven't read past book one.
2003 anime verse
-X-
Of the Unknown
It wasn't the wave of sickness that Edward felt bottle in his gut that told him that the people in front of him weren't human. No, for even their mysterious powers could've easily been mistaken for alchemy. The thing that shocked Ed the most was the lack of daemon.
None of them had one. They stood there talking, dishing out threats and making their deals and Ed could only stare in wonder. They were artificial human being. He'd never seen anything like them. They weren't supposed to even exist, yet they stood there in front of them with no daemon in sight. They were completely soulless entities.
Fia's hair stood on edge, and she rubbed herself against his legs, clinging to him after witnessing the sight of such lonely creatures. Ed could barely hear the soft purring noises she was making. He wished he could pick her up, just to hold her close in reminder that she was there and his.
The tallest of the three homunculi, the female, smiled at the sight of Fia, and Ed swallowed nervously.
The homunculi wanted to become human.
They wanted souls; they wanted a daemon.
Edward pushed Fia back behind him with his leg.
And the homunculi would have to use the power accumulated in other people's daemons to do so.
-X-
Long Author's Note: Ideally, the name for Ed's daemon would be ridiculously long, but the daemon of Lyra (the main character of The Golden Compass) has a shorted name or nickname. So due to my laziness, I decided I would only refer to her by a nickname for a nonexistent name.
Fia is a black footed cat, the smallest breed of African cat, but one of the most aggressive. All have golden eyes. (I'm not a cat freak, I swear, my best friend is. That's how I know this stuff.)